TRNG I HC GIAO THNG VN TI TP. H CH MINHV Ngc Bch

KT CU TU THYTP I

Thnh ph H Ch Minh - 2007

M UGio trnh Kt cu tu thy bao gm hai phn, phn th nht trnh by nhng vn tng quan v kt cu tu thu. Phn th hai trnh by vic tnh ton kt cu tu theo lut ng tu. Ni dung chnh cp trong gio trnh tp I ny bao gm: Gii thiu v tu v h thng kt cu thn tu. Trnh by s lc v vt liu ng tu. Cc chi tit kt cu tu v thp. Gio trnh trnh by nhng hiu bit mang tnh ph thng, gip ngi c bit v hiu v kt cu tu thu, nm bt nguyn tc b tr, thit k kt cu tu. Gio trnh c bin son cho sinh vin chuyn ngnh thit k, ng v sa cha tu thu. Gio trnh cng c li cho nhng ngi lm vic ti cc x nghip ng, sa cha tu, cng trnh ni v nhng ngi qun l k thut tu thy. Mc du c nhiu c gng, song ngi bin son nhn thc rng, trong ti liu khng chc trnh c cc sai st v khim khuyt. Hy vng rng, ng nghip cng bn c gn xa, gp thm nhiu kin cng xy dng gio trnh hon chnh, phc v ngi c tt hn. Mi ph bnh, gp xin gi v: KHOA NG TU THU V CNG TRNH NI, S 2, ng D3, khu Vn Thnh Bc, phng 25, qun Bnh Thnh, thnh ph H Ch Minh, in thoi/Fax: (08) 8035 655 hoc Email: vubichchhp@yahoo.com.

TS. V Ngc Bch

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MC LC Trang M u Mc lc Chng 1 1 1.1 1.2 1.3 1.4 1.5 1.6 1.7 2 3 4 4.1 4.2 4.3 4.4 4.5 5.6 Chng 2 1 2 3 4 5 5.1 5.2 5.3 5.4 5.5 5.6 5.7 5.8 5.9 Gii thiu tu v kt cu thn tu Cc kiu tu thng dng Tu ch hng kh Tu ch hng lng Tu ch khch Tu chuyn ngnh Tu phc v khai thc du kh trn thm lc a Tu nh bt v ch bin c Tu cng tc hot ng trn nguyn tc kh ng hc ng kim tu thu Cng c Quc t lin quan n ng tu Vt liu ng tu Thp ng tu Kim loi mu Thp bn cao Hp kim nhm G Vt liu composite (cht do ct si thu tinh) H thng kt cu thn tu H thng kt cu thn tu H thng kt cu ngang H thng kt cu dc H thng kt cu hn hp ngang-dc Kt cu cc tu vn ti thng dng Tu vn ti hng kh Tu ch du Tu ch hng ri Tu ch hng thng tiu chun (container) Tu ch kh ho lng (Liquid Gas Carriers) Tu khch Tu nh bt c Cng trnh ni ngoi khi Tu c nh 2 3 5 5 5 8 9 11 12 14 14 15 16 17 17 19 19 21 23 25 28 28 34 37 40 43 43 45 54 66 75 78 82 86 92 3

5.10 Tu trn cnh ngm ch khch Chng 3 Chi tit kt cu thn tu 1 2 2.1 2.2 3 4 5 6 7 8 Chi tit kt cu thn tu Dn y y n y i Mn Boong Kt cu phn mi Kt cu phn li Vch V bao

95 98 98 100 100 104 117 128 148 159 169 182 188 189 193 194 195 202 210 210 214 220 224 225

9 Vy gim lc 10 Vm trc chn vt Chng 4 1 2 3 Thng tng v lu Lu mi Thng tng Be gi

Chng 5 Kt cu bnh li, b my, ng khi 1 Bnh li 2 B my 3 Ong khi Ti liu tham kho Bng k thut ng v kt cu tu

CHNG 14

GII THIU TU V KT CU TU1. Cc kiu tu thng dng Tu thu l cu trc ni, c hoc khng c ng c, chuyn dng hot ng trn mt nc. Tu thy c pht trin t rt sm trn tri t, dng vo cc vic chuyn ch ngi, hng ha. Tu thy cn c pht trin phc v cho qun i. Trc khi lm quen vi kt cu tu c th, bn c c dp tm hiu cc kiu tu ang tn ti cng cc c trng kt cu ca chng. Tu thy chia lm hai nhm chnh l tu dn s v tu qun s. Trong h tu dn s li gm nhng nhm nh: 1.1. Tu ch hng kh Tu nhm ny c mt trn tri t lu i nht. Ty thuc loi hng m tu chuyn ch, ngi ta t tn tu. Tn gi chung nht l tu ch hng (cargo ship), bn cnh cn tu ch hng ri (bulk carrier), tu ch hng thng (container), tu Ro-Ro (roll on roll of), tu ch s lan (barge carrier), tu ch g (timber carrier), tu ch hng lnh (refrigerated cargo ship), tu chuyn ch xe, thit b (car carrier) vv... Tu ch hng kiu c chim hn 50% s lng tu vn ti trn th gii. Sc ch tu loi ny khng ln lm, thng t 4.000 dwt n 10.000dwt. Ln nht trong nhm ny l tu hng sc ch 20.000dwt. Hnh 1.1 l loi tu hng c thng tng gia (tu ba o - middle three island cargo vessel) ra i vo khong gia th k XX, hnh 1.2 l loi tu hng c bung my t ui (tu hai o aft engine type cargo vessel) xut hin trong thp nin 70 ca th k XX, hnh 1.3 gii thiu tu hng i bin hin i.

Hnh 1.1. Tu ch hng kiu 3 o (1950) Tu ch container (hnh 1.4) xut thn t tu ch hng kh vi c tnh hng c bo qun trong cc thng chuyn dng loi di 20 ft hoc 40 ft, tiu chun ha. Tu container thng ch to vi sc ch t vi ngn dwt n 25.000dwt. Ra i mun hn so vi i tu container l tu RO-RO (roll on roll of) chuyn ch cc thit b k thut c bnh xe (hnh 1.5). Vn tc khai thc tu container v tu RO-Ro kh ln, khong 20-25 HL/h.

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Hnh 1.2. Tu ch hng kiu 2 o (1970)

Hnh 1.3. Tu vn ti i bin hin i (1983)

Hnh 1.4. Tu ch container (1993) Tu ch hng lnh chuyn ch t rau qu n c, tht, thc phm. Nhit bung lnh khong +5C n -25C. Tu ch s lan c nhc n nhiu l tu LASH (Lichter Abroad Ship), ch cc s lan khng t hnh (hnh 1.6). Sc ch mi s lan t 370 tn n 850 tn. Nhm LASH dng cn cu di ng sc nng 500T dch chuyn s lan dc tu. Tu SEA-BEE s dng cn cu c nh t pha li nng h s lan. 6

Hnh 1.5. Tu Ro-Ro (1978)

Hnh 1.6. Tu ch s lan (1969) Tu ch hng ri c chuyn nghip ha vn chuyn qung, than , khong sn, cc loi ht ri khng ng gi (hnh 1.7). Tu nhm ny tuy gi chung l tu ch hng ri, song nhim v c th phi c t tn gi chuyn ngnh nh tu OO (Ore-Oil) ch qung lc i, ch du lc v, tu OBO (OreBulk-Oil), tu OSO (Ore-Slurry-Oil). Tu nhm ch hng bulk c sc ch kh ln, t 100.000dwt n 150.000dwt hoc hn.

Hnh 1.7. Tu ch hng ri (1978) 7

Ngoi ra, cn c nhm tu chuyn ch nng (heavy cargo ship), hay cn c gi l hng siu trng, siu trng l hng c kch thc hoc trng lng thc t ca mi kin/khi hng vt qu gii hn quy nh cho php nhng khng th tho ri ra c (hnh 1.8).

Hnh 1.8. Tu ch hng nng (1995) 1.2. Tu ch hng lng. Trong nhm ny tu ch du (tanker) dn u v sc ch v kch thc chim ch. Lot tu du khng l, sc ch trn 540.000 tn c a vo s dng t hng chc nm trc. Tu ch kh ha lng (liquefied gas carrier) v tu ch ha cht (chemical carrier) thuc nhm ny. Tu ch sn phm du chy sng hay bin gi chung l tanker. Sc ch thng thng tu du t 1000dwt n tu c ln, sc ch 300.000dwt n 540.000dwt. Tu ch kh ha lng gm kh thin nhin LNG v kh thuc ngnh du kh LPG. Cc kh c nn v lm lnh n m 161,5C khi vn chuyn.

Hnh 1.9. Tu du i bin (1992)

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Hnh 1.10. Tu du chy sng

Hnh 1.11. Tu ch kh thuc gc du ha lng (LPG)

Hnh 1.12. Tu ch kh kh thin nhin ha lng (LNG) 1.3. Tu khch. Tu ch khch bao gm tu a ngi qua li trn tuyn ng ngn chng ta cn gi ph (ferry car) n tu khch tuyn ng di, c nh, chuyn ngnh gi l linear, tu tuyn c nh. Tu khch dng ch ngi hoc ch ngi cng hng ha. C th phn bit thm, tu va ch khch v hng ha cn c tn gi tu hng khch. Tu hot ng tuyn c nh thng c kch thc 9

ln, trang b tin nghi y , lng chim nc n 70.000T, lng khch n 1.500 hoc 2.000 ngi, hnh 1.13 gii thiu ph khch chy bin; hnh 1.14 gii thiu tu khch du lch chy bin mang tn Star leo, sc ch 1400 khch. Tu du lch ch khch tuyn ngn, s lng khch trn tu khng ng.

Hnh 1.13. Ph khch chy bin

Hnh 1.14. Tu khch chy bin

Hnh 1.15. Tu khch du lch chy sng 10

1.4. Tu chuyn ngnh Nhm tu ny a dng, chuyn su vo mt hoc mt s lnh vc phc v k thut. l cc tu ko (tug), tu cu ho (fire vessel) tu cu h (salvage vessel), tu th phao, m bo an ton hng hi (buoy vessel), tu t cp ngm (cable layer), tu cuc bn, tu ht bn lm cng tc no vt lung lch, cng (dredger), tu hoa tiu (pilot craft), tu hi quan (custom boat), tu kim ng (fisheries patrol boat), tu hun luyn (training ship)vv .

Hnh 1.16. Tu th phao

Hnh 1.17. Tu ko cu ho ti cng

Hnh 1.18. Tu t cp ngm 11

Hnh 1.19. Tu ht bn

Hnh 1.20. Tu hun luyn 1.5. Tu phc v khai thc du kh trn thm lc a (offshore vessels) Nhm tu ny bao gm cc tu lm dch v cung ng (supply ship), tu t ng ngm(pipe layer), cn cu ni (crane barge), gin khoan ni gm gin na chm v gin t nng (semisubmersible drill rig, jack-up rig), tu khoan (drill ship) v cc cng trnh ni phc

Hnh 1.21. Cn trc ni 12

Hnh 1.22. Tu dch v cung ng

Hnh 1.23. Tu khoan

Hnh 1.24. Dn khoan t nng

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Hnh 1.25. Dn khoan bn chm 1.6. Tu nh bt c v ch bin c Tu c chim n 5% ti trng ca i tu trn th gii. Tu nh bt gm tu li ko, tu li vy, tu lm ngh li r vv Tu ch bin dng nhng c s sn xut kh ln trn bin.

Hnh 1.26. Tu nh c li vy 1.7. Tu cng tc hot ng trn nguyn tc kh ng hc Nhng tu nh tu cnh ngm (hydrofoil craft), tu trn m kh (hover craft) thuc nhm ny.

Hnh 1.27. Tu cnh ngm

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Hnh 1.28. Tu m kh 2. ng kim tu thy ng kim tu c tn gi st ngha l c quan phn cp tu, trong ting Anh c vit l Classification Society, ngi Trung Hoa gi bng t thuyn cp x, trong ngn ng ca ngi Nht dng cm t ny c hiu theo m Hn Vit l hi s hip hi. Nhn chung, nhim v chnh ca cc c quan phn cp tu l gim st k thut v phn cp ph hp vi cc yu cu c qui nh bng lut. ng kim Vit Nam (gi bng ting Anh l Vietnam Register) l c quan gim st v phn cp tu, thc hin cng tc gim st k thut, phn cp, nh mn kh, o dung tch tu, gim st vic thc hin cc yu cu ca Cng c quc t c lin quan m Vit Nam tham gia. i tng kim tra, gim st ca c quan phn cp l cc loi tu ni chung, cc my mc, trang thit b dng trn tu, cc cng trnh trn bin cng tt c trang thit b trn . Cc c quan ny tin hnh hng lot cng tc nghin cu khoa hc lin quan n thit k, ch to, bo dng, duy tu tu v trang thit b ng thi a ra cc qui phm (gi bng ting Anh l Rules and Regulations) lin quan n bn, an ton tu cng trang thit b. Cc c quan phn cp c uy tn trn th gii, c lin quan n cng nghip ng tu Vit Nam c th k l: ng kim ra i sm nht l Lloyds Register of Shipping thuc vng quc Anh. LR ra i nm 1760, c ci t 1834. T nm 1914 c quan ny mang tn trn cho n ngy nay. LR c i din thng tr ti Vit Nam, tham gia cc hot ng ng tu, sa tu v cng trnh bin ti Vit Nam. Qui phm tu bin ca LR mang tn Rules and Regilations for the Classification of Ships. Det Norske Veritas thnh lp nm 1864 ti Oslo, Norway. Qui phm ng tu DNV Rules for Ships c trnh by sng sa, d hiu v trong chng mc l chun mc cho vic xc lp cng thc qui phm. DNV c i din ti Vit Nam, l ng kim tham gia rt nhiu cng trnh ti Vit Nam. ng kim Lin x trc y v nay ng kim Lin bang Nga. ng kim URSS thnh lp li nm 1924 ti Leningrad, t c quan mang tn Ruskij Registr lp nm 1914. Cc qui phm ca ng kim URSS l nguyn mu cho cc qui phm chng ta dng n t nhng nm 1985 - 1997. Tn ghi ti ba qui phm URSS cng l tn gi ngoi ba ca qui phm Vit Nam Rules for the Classification and Construction of Sea-going Ships . Ngy nay tn gi chnh thc ca ng kim ny bng ting Anh l Russian Maritime Register of Shipping (RMRS). 15

ng kim M American Bureau of Shipping, thnh lp t 1867, tr ng ti New York t 1898 di tn gi American Standard Universal Record of Shipping. Ngy nay ng kim trn mang tn gi nh trnh by trong dng ch m, vit tt ABS. Qui phm ca ABS mang tn Rules for Building and Classing Steel Ships. ng kim Nht bn c tn gi Nippon Kaiji Kyokai, vit tt NKK, thnh lp t 1899, tr s ti Tokyo. Tn gi chnh thc ca NKK, dch ra m Hn Vit c hiu l :Nht bn hi s hip hi. ng kim NKK gip nhng ngi ng tu Vit Nam rt nhiu, t hng dn, o to, gip trong cng tc chuyn mn n cho php dch qui phm ca NKK Rules and Regulations for the Construction and Classification of Ships thnh qui phm s dng chnh thc t 1977 ti Vit Nam. ng kim Trung quc c tn gi bng ting Hn l Trung quc thuyn cp x , vit bng ting Anh China Classification Society - CCS, khai trng cng vic t 1956. Qui phm ng tu i bin do CCS a ra mang tn gi nh Cng cht hi thuyn nhp cp d kin to qui phm - dch thnh: Qui phm phn cp v ng tu i bin v thp c ngha thc t. ng kim Php Bureau Veritas thnh lp 1828, t 1832 tr s ng ti Paris. BV tham gia mt s cng trnh ti Vit Nam. Cc ng kim va nu u thuc Internatinal Association of Classification Societies - IACS, c quan h mt thit vi ng kim Vit Nam (VR). i tng gim st ca ng kim thng thng l: (a) Tt c cc loi tu bin (ang cp qui phm tu bin) c qui nh c th bng vn bn. ng kim Vit Nam, ging nh ng kim NKK, gim st cc i tng k sau: Tu hng, Tu khch, Tu du, Tu ch x kh ha lng, Tu ch x ha cht nguy him, Tu cng nghip hi sn, Tu nh c, Tu c cng dng c bit, Tu ch hng thng, (container)

(b) Thit b lm lnh hng t trn tu. (c) Cng te n vn chuyn hng ha, k c cont te n cha hng ha. (d) Thit b nng hng tu bin. (e) Vt liu, sn phm lp t trn tu bin. Nhng con tu nm trong phm vi gim st ca ng kim ch c php hot ng khi c ng kim cp s ng k km theo h s v chng nhn phn cp c ng kim thng qua. 3. Cng c quc t lin quan n ngnh ng tu Cc cng c quc t thng l c t chc hng hi quc t c tn gi Inter-Government Maritime Organization, vit tt IMO, son tho, hiu chnh v khuyn co lu hnh ti tt c cc nc lin quan hng hi. T chc hng hi ny do hi ngh v hng hi ca Lin Hp Quc hp ti Geneve 16

1948 thnh lp vi tn gi ban u T chc t vn hng hi lin chnh ph, vit tt IMCO. Nhng cng c ra i t cc hi ngh IMO nhm mc ch m bo an ton mng ngi trn bin, an ton hng hi, an ton phng tin v cc bin php chng nhim mi trng. Nhng tu c thit k v ch to hot ng trn bin nht thit phi tun th nhng qui nh ngt ngho t ra trong cc cng c quc t. Mt s cng c lin quan n ngnh tu nh sau: International Convention for Safety of Life at Sea, 1948. Vit Nam tham gia Cng c quc t v an ton sinh mng con ngi trn bin, 1974, vit tt SOLAS, 74. International Convention for Safety of Life at Sea, 1960 International Convention for Prevention of Pollution of the Sea by Oil, 1954 as amended in 1962. Cng c quc t v ngn nga nhim bin do tu gy ra, 73/78, MARPOL, 73/78 International Convention on Load Lines, 1966. Cng c v mn kh tu bin, 1966, LOAD LINES, 66. International Convention on Tonnage Measurement of Ships, 1969. Cng c quc t v o dung tch tu bin,1969, TONNAGE, 69. International Convention relating to Intervention on the High Sea in cases of Oil Pollution Casualties, 1969 International Regulations for Preventing Collisions at Sea, 1972. Qui tc quc t trnh va trn bin, 1972, COLREG, 72.

4. Vt liu ng tu 4.1. Thp ng tu Thp lm v tu thng l thp cacbon, cha t 0,15% n 0,23% cacbon cng lng mangan cao. Hai thnh phn gm lu hunh v pht pho trong thp ng tu phi mc thp nht, di 0,05%. T nm 1959 cc ng kim ng tiu chun ha thp ng tu nhm gim thiu cc cch phn loi thp dng cho ngnh ny, trn c s m bo cht lng. Theo tiu chun c chp nhn ny, c 5 cp thp, t k thut bng ting Anh vit l grade, cht lng khc nhau, dng cho tu thng mi. l cc cp A, B, C, D v E. Thp cp B dng ti nhng vng nhy cm vi tc ng lc, nhng ni i tm c chiu dy ln. ng kim ABS ghi r rng thp grade B vo danh mc thp dng lm thn tu. V sau ny nhiu nc khng ghi cp C vo danh mc cc cp thp ng tu. Theo cch ghi trong qui phm do ng kim Vit Nam a ra, cp thp chp nhn ti mc phn loi thp, iu 3.1.2- Qui phm phn cp v ng tu bin v thp, 2003, gm A, B, D, E. Nhng yu cu i vi thp ng tu, bn bnh thng. Bng 1.1 Grade Cacbon, % Mangan, % Phospho, % Lu hunh,% Silic, % Ni,Cr,Cu, % A 0,21 max 2,5min x cacbon 0,035 max 0,04 max 0,50 max B D 0,21 max 0,21 max 0,6 min 0,6 min 0,035 max 0,035 max 0,04 max 0,04 max 0,35 max 0,10-0,35 t hn 0,02% E 0,18 max 0,035 max 0,04 max 0,10-0,35 Ghi ch

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bn vt liu Gii hn bn tt c cc nhm: 400 490 N/mm2(4100-5000 kG/cm2) Thp hnh grade A : 400 550 N/mm2 Gii hn chy ca tt c cc nhm : 235 N/mm2 (2400kG/cm2) Thp grade A, dy trn 25 mm : 220 N/mm2( 2250 kG/cm2) Cc k hiu va nu trong phn vt liu ny c dng ti hu ht cc nc. Trong ti liu chnh thc do ng kim Vit Nam lu hnh, yu cu chung cho tt c 4 cp, theo TCVN 6259-7:2003 l: Bng 1.2 Cp thp A B D E Gii hn chy (N/mm2) 235 Th ko Gii hn bn (N/mm2) 400 520 gin di, % 22

Ngun cung cp thp ng tu kh phong ph. Chn thp cho kt cu cn bit xut x v cc tiu chun dng thp c chn. Mt s h thng qui tc bt buc p dng khi dng thp sn xut ti USA c th k sau y. H thng phn loi quan trng nht ca USA l AISI (American Iron and Steel Institut), theo h thng ny cp thp c dng 4 con s ch. S th nht ch cacbon, con s th hai ch lng phn trm hp cht chnh yu trong . V d 10XX ch thp cacbon. Hai con s cui ch lng cacbon, tnh bng phn trm, v d AISI 1040 ch thp cacbon cha 0,04% cacbon. Cc k hiu theo h thng ASTM (American Society for Testing Materials) mang c trng d nhn din, c dng chnh thc trong vn bn ca ng kim ABS. Thp thng dng trong ng tu thuc nhm A36-78, l thp cacbon, dng trong xy dng. Hai con s cui cng trong k hiu ASTM ch nm ra i ca phin bn mi nht. Thp tm, thp hnh, ng vv thng c phn loi trong h thng ny. Thp bn cao ghi trong h thng ny gm A242, A440, A441, v A588, vv Thp dng ch to chi tit c ghi bng k hiu ca n. Nhng k hiu ca kim loi v hp kim qui nh trong TCVN 1659 75 c tm tt nh sau: Thp cc bon thng thng (thp xy dng), k hiu bng CT v cc con s i sau ch bn ko, tnh bng daN/mm2. Thp nhm ny c th l CT31, CT33, CT34, CT38, CT42, CT51, CT61. Thp cac bon cht lng tt k hiu bng k t C. Con s i sau C ch hm lng cac bon, tnh bng phn vn, 1:10.000 . V d thp ca nhm C5, C8, C10, C15, C20, C25, C30, C40, C70, C85. Thp cng c k hiu bng CD, v d CD70, CD80, CD0, CD100, CD120. Thp hp kim ghi theo cch c dng ti Vit Nam nh cc v d: 10Mn2Si, 9Mn2, 10SiMnPb, 100Cr2 vv Trong cc sch k thut dng ti nc ta, cho n nhng nm chn mi ang s dng cc k hiu phn loi ca Nga t rt lu v c chuyn ha theo cch hiu ca ngi khng phi Nga. T cui nhng nm chn mi, ngi Nga s dng nhng tiu chun chung nh cc nc khc trong cng ng th gii, cch k hiu cng c nhng i mi. C l v s thay i t ngun cn gii thch r bn c d i chiu vi cc tiu chun va nu. Thp ng tu dng ti Lin x trc y c qui nh trong tiu chun nh nc lin bang, v d GOST 5521-50, t nm 1950, hoc trc , theo cc thp CT.3C, CT4C theo cch vit ca ngi Nga (nu phin m thnh Latinh cc k hiu phi c hiu l St 3S, St 4S) c dng nh thp bn bnh thng. K hiu ca ngi Nga mang ngha 18

CT - vit tt t thp, C vit tt ng tu. Thnh phn ca cc thp ng tu theo qui nh trong GOST 5521-50 v sau nh sau: Bng 1.3 Mc thp CT.3C CT.4C C, % 0,14 0,22 0,18 0,27 Si , % 0,12 0,35 0,12 0,35 Mn, % 0,35 0,60 0,4 0,7 S, % 0,05 0,05 P, % 0,05 0,05

Yu cu v gii hn chy v gii hn bn: CT.3C: CT.4C: khng nh hn 220 MN/m2; 380 470 MN/m2 khng nh hn 240 MN/m2; 420 520 MN/m2

Trong mt s tiu chun GOST c cng b nhng nm gn y, s dng gii hn di ca bn chy kt hp vi mc thp tiu chun quc t ISO. i vi thp ch to tu thuyn, theo GOST 5521-89 c hai loi u c tnh hn. Mt l loi thp c bn thng thng, c 4 mc thp A, B, C, D, gii hn chy l 235MPa; mt l loi thp c bn cao, mc thp l A x x, D x x, E x x. Trong x x biu th cp bn, v d A32 biu th cp 32 kG (tc 315 MPa), D40 biu th cp 40 kG (tc 395 MPa). 4.2. Kim loi mu ng kim loi k hiu bng Cu, gm Cu1, Cu2, Cu3 Cu1 ng kim loi cha 99,9% Cu; Cu2 ng kim loi cha 99,7% Cu; Cu3 ng kim loi cha 99,5% Cu. Latng (ng thau) k hiu L. V d LCuZn20, LCuZn40Pb2 Brng (ng thanh) k hiu B. V d BCuSn2, BCuSn6Zn6 uara, v d AlCu4Mg2. 4.3. Thp bn cao Theo tiu chun c cc nc chp nhn, thp bn cao dng trong ng tu c phn cp thnh ba mc, k hiu 32, 36, 40. Mi mc bn c chia lm bn cp: AH (v d AH32, AH36, AH40), DH (v d DH32, DH36, DH40), EH ( EH32, EH36,EH40). Mc bn cao hn, tnh t 42, 46, 50, 56, 62 v 69 c ghi vo cc grade FH. Theo tiu chun Vit Nam, thp cng cao c chia lm cc cp sau y: A 32, D32, E 32, A 36, D36, E 36, A 40, D 40, E 40, F32, F36 , F40. Thnh phn ha cht trong thp bn cao khng qu gii hn sau: Cacbon Mangan Phospho Lu hunh Nickel Gii hn bn : 0,18 % max; : 0,90 1,6 % : 0,04% max; : 0,04 % max; : 0,4 % max; Chrom Molybdem ng Silic Vanad : 0,25% max; : 0,08 max; : 0,35 % max; : 0,1 0,5 %; : 0,10 % max.

: H32 470 -585 N/mm2 (4800-6000 kG/cm2 ) 19

H36 H40

490-620 N/mm2 (5000-6300 kG/cm2) 510 650 N/mm2 (5200 6600 kG/cm2)

Gii hn chy : H32 315 N/mm2 (3200 kG/cm2) H36 H40 355 N/mm2 (3600 kG/cm2 ) 390 N/mm2 (4000 kG/cm2 ) cho mc 40; 22% cho mc 32.

gin di tng i : 20%

Tnh cht c hc ca cc cp thp cng cao: Bng 1.4 Cp thp A 32 D32 E 32 F32 A 36 D36 E 36 F36 A 40 D40 KE 40 KF40 Gii hn chy (N/mm2) 315 Th ko Gii hn bn (N/mm2) 440 590 gin di, % 22

355

490 620

21

390

510 650

20

Tnh cht c hc cc mc thp sn xut ti Lin trc y, k hiu cn lu li trong ti liu Vit Nam c ghi li nh sau. Bng 1.5 Mc thp (Nga) CX-1 CX-1 MC-1 092 M MK CX-45 KC Gii hn chy MN/m2 350 400 400 300 300 350 450 450 Gii hn bn MN/m2 520 540660 540660 450 480620 500640 560680 560680 gin di 10 % 18 16 16 18 1817 16 16 15

S dng cc cp thp vo kt cu tu theo ng chc nng ca chng. Cc nh ng tu cc nc tun th qui nh gn nh thng nht sau, trch t qui nh ca RMRS (Russian Maritime Register of Shipping).

20

Bng 1.6 C cu Cp thp 0 Loi hai A B D E A32,A36,A40 D32, D36, D40 E32, E36, E40 A B D E A32, A36, A40 D32, D36, D40 E32, E36, E40 A B D E A32, A36, A40 D32, D36, D40 E32, E36, E40 30 40 50 50 40 50 50 20 25 35 50 25 45 50 15 20 50 15 30 50 Nhit thit k dng cho vt liu, C -10 -20 -30 -40 Chiu dy c cu, mm, khng qu tr ga sau 20 10 30 20 10 40 30 20 10 50 50 50 45 30 20 10 50 45 35 25 50 50 50 45 10 20 10 25 20 10 50 50 40 30 20 10 40 30 20 10 50 50 40 30 10 45 35 25 10 20 10 45 35 25 10 -50 35 15 35 20 20 -

Loi mt

Hng c bit

Chiu dy cc tm hoc chiu dy thnh thp hnh ca ba cp A, B, D c cp ti y khng qu 50mm. Chiu dy ti a cp E ch c tnh 100mm. C th hn na, thp cp A, B thng ha c cung cp di dng chiu dy khng b hn ch trong gii hn, hiu n gin hn, thp cn thuc cp A, B c chiu dy bt k. Thp cp D chiu dy n 25mm c th l thp lng v x l ht mn ( steel is killed and fine grain treated). Thp cp D dy trn 35mm qua lng v x l ht mn cn phi chu th va p. 4.4. Hp kim nhm Vt liu truyn thng lm tu c nh, chy nhanh l hp kim nhm. Trn th trng quc t gi vt liu t hp kim nhm cao hn 10 ln thp cng trong lng. trong lng ring ca nhm thc ra ch bng 35% trong lng ring ca thp, do vy gi thnh tnh cho n v th tch vt liu, gi hp kim nhm ch cao hn thp 4 ln. iu c th ni, nu c gii hn bn ca hp kim nhm khng cch xa nhiu so vi thp thng, v mt l thuyt c th tit kim 65% trong lng vt liu nu thay th bng nhm. Trong thc t gii hn bn ca nhm thp hn do vy mc gim trong lng ti a khi thay thp bng nhm ch khng n 50%. Hp kim nhm dng ng v tu thng cha mangan nh cht b sung chnh. Hp kim ny chu c tc ng ca nc bin, trong khi bn ca n kh cao. Theo phn loi dng ti UK hp kim nhm dng trong ng v tu (marinealuminim alloys) c phn thnh 5 nhm chnh, k hiu N4, N5, N6, N8 v H30, tng ng cc phn loi ca ISO l A1Mg2, A1Mg2, A1Mg3-5, A1Mg3-5, A1Mg5, A1 Mg 4-5 Mn v A1SIMgMn. c tnh c hc hp kim nhm va nu nh sau: module n hi E = 69 Gpa, module ct G = 25 GPa bn ko nhm N4: 160-225 MPa, nhm N8:125-270 MPa, v ca H30:120-240 MPa. 21

Theo cch phn loi ca Nga, hp kim nhm mangan c ch to theo cc m AMg2, AMg3, AMg6, AMg61, v cc m khc. c tnh c hc cc tm cn t hp kim nhm sn xut ti Nga c xc nhn theo tiu chun nh nc OCT 261631, (GOST 261631). Theo tiu chun ny hp kim AMg2 c cc tnh cht: bn ko u = 176,4MPa, gii hn chy y = 147 MPa, gin di tng i a = 7%. Hp kim AMg3 c cc tnh cht: bn ko u = 186,2 MPa, gii hn chy y = 78 196MPa, gin di tng i a = 12 15%. Hp kim AMg4 c cc tnh cht: bn ko u = 235 MPa, Gii hn chy y = 98 MPa, gin di tng i a = 12%. Theo qui nh ghi trong quy phm ng tu v hp kim nhm ca DNV, c tnh c hc ti thiu p dng cho vt liu lm v tu phi l: Bng 1.7 Vt liu A1Mg3Mn A1Mg4 AMg4,5Mn AMsSil bn ko, MPa 240 250 270 170 Bng 1.8 Vt liu A1Mg4 A1Mg3Mn A1Mg4,5Mn A1MgSil Tiu chun tng ng ISO2 AA3 A1Mg4 5086 A1Mg3Mn 5454 A1Mg4,5Mn 5083 A1MgSil Si Max0,5 Max0,5 Max0,5 Max0,5 Thnh phn ho hc,% Mg Mn 3,5-4,6 Max0,8 2,4-3,4 0,3-1,0 4,0-4,9 0,3-1,0 0,4-1,0 Cht khc Cu: 0,1 F: 0,5 Cr: 0,35 Zn: 0,20 Ti: 0,20 Gii hn chy, MPa 110 110 145 115

Thnh phn hohc cc hp kim ny phi nm trong phm vi sau:

Cp v c tnh hp kim nhm cn dng lm v tu chy nhanh ghi trong TCVN 6451-2:1998 c trch dn ti bng di y. Lu bn c, m hiu c c quan c thm quyn Vit Nam dng cho hp kim nhm phi c hiu theo hon cnh c th. Trong bng sau, nu khng gii thch thm k hiu bng s khng khc k hiu c t chc AA (Aluminium Association) s dng. K hiu ch i sau s phi c i chiu vi gii thch do c quan c thm quyn nu. ng sut trong bng tnh bng Mpa. Bng 1.9 Hp kim nhm Nhm Nhm 5052 Cp 5052 P-O 5052 P-H32 5052 P-H34 5052 S-O 5052 S-H-112 22 Chiu dy t mm 75 12 12 130 130 Th ko Vt liu c bn ng sut th 65 min 155 min 175 min 70 min 70 min bn ko 175~125 215~265 235~285 175~245 175 min Lin kt hn bn ko 175 min

Nhm 5083

40 12 40 38 130

125~265 215~295 215~295 120 min 110 min 125 min 110 min 110 min 95 min 230 min 180 min 245 min 245 min 205 min 175 min

275~355 305~385 305~385 275~355 275 min 255 min 245 min

275 min

Nhm 5086

6,5 6,5< t 13 13< t 25 25< t 50 5086 S-H112

245 min

130

240 min 315 min 290 min 295 min 265 min 245 min 225 min

245 min 285 min 167 min 157 min

Nhm 5456 Nhm 6000

5456 P-H116 5456 S-H111 6061 P-T6 6061 S-T6 6N01 S-T5

30 130 6,5 12 6 6 < t 12

C hai loi vt liu truyn thng ny khi lm v tu i hi qui trnh bo dng rt nghim ngt. Tu phi c co h sn ln thng xuyn, b mt v tu phi m bo nhn gn vi mc khi xut xng tu c th pht huy tc tnh ton. Thc t cho thy, v tu thp c sc hp dn vi cc sinh vt bin trong mi trng nhit i v iu ny lm cho b mt v tu b nhm rt nhanh. c trng hp tu cao tc v thp c vn tc thit k 28 Hl/h, ch sau thi gian u ti bn ba tun b h bm bm tng sc cn v tu n mc khi chy li vn tc tu khng vt qua c 15Hl/h. 4.5. G G dng trong ng tu rt a dng. Tnh cht c hc ca vt liu ny khc nhau rt nhiu gia cc nhm g. D liu nu tip y c tnh theo gi tr trung bnh. Trng lng ring ca g thay i t g nh, v d thng: 600650 kg/m3 n 900 kg/m3 cho g cng. Tnh cht c hc ca g c xc nh theo nhng yu cu c bit ca ng kim. bn ko dc th vo khong 5060 MPa. Theo TCVN 1072-71 g dng trong ng tu c chia thnh 6 nhm theo tnh cht c l. - G nhm I, nhm II v nhm III c dng ch to khung xng ca tu. - Khng c dng g nhm IV, nhm V v nhm VI lm sn, sng mn v m ni, sng ui, sng mi, trc li, ng bao trc chn vt v b my. - Vn v v vng di ng nc phi l g nhm II hoc nhm III. Vn v vng trn ng nc v vn boong c th l g nhm IV. Vn bao ca thng tng v ca lu c th l g nhm V. Vn vch ngang kn nc c th l g nhm IV. G dng ng tu phi c sy kh, c m t 15 22%, khng b xin th. 23

TCVN 1072-1971: G Phn nhm theo tnh cht c l 1. Tiu chun ny dng cho cc loi go dng chu lc. Ch yu l xy dng v trong giao thng vn ti. 2. Cc loi g c chia thnh su nhm theo ng sut nn dc, un tnh, ko dc v ct dc nh quy nh trong bng 1.10. Bng 1.10 5 ng sut, 10 N/m2(1N/m2=105 kG/cm2) Nhm nn dc un tnh kodc ct dc I II III IV V VI T 630 tr ln 525-629 440-524 365-439 305-364 T 304 tr xung T 1300 tr ln 1080-1394 900-1079 750-899 625-749 T 624 tr xung T 1395 tr ln 1165-1394 970-1164 810-969 675-809 T 674 tr xung T 125 tr ln 105-124 85-104 70-84 60-69 T 59 tr xung

3. i vi cc loi g cha c s liu v ng sut th tm thi da theo khi lng th tch chia nhm nh trong bng 1.11. Bng 1.11 Nhm I II III VI V VI Khi lng th tch T 0,86 tr ln 0,73-0,85 0,62-0,72 0,55-0,61 0,50-0,54 T 0,49tr xung

4. Khi tnh ra cc tr s tnh ton th dng cc tr s ng sut qui nh trong bng 1.12. Bng 1.12 ng sut, 105N/m2 Nhm I II III 24 nn dc 630 525 440 un tnh 1300 1080 900 Ko dc 1395 1165 970 ct dc 125 105 85

IV V VI

365 305 205

750 625 425

810 675 460

70 60 45

4.6. Vt liu composite (cht do ct si thu tinh) Vt liu composite FRP dng c kt qu lu nay gm nha polyester khng no v si thu tinh. Vt liu ny thng c vit tt t ting Anh kiu M l FRP hoc theo cch vit ca ngi Anh l GRP. Nhng thng tin v vt liu do cc hng sn xut nc ngoi cung cp, thng tin v cng ngh lm vt liu composite c cc trng i hc Anh, M v t chc nng lng th gii FAO ti Rome, cng chi nhnh ca t chc ny ti ASIAN cung cp. Cc mu tu chy nhanh thng dng lm t vt liu composite c cc nh my lm tu chuyn dng ca hng Transfield (Uc), t hp cng nghip quc phng hunting (Vng quc Anh), Robert Allan (Canada), Simonneau (Php), Cng ty cng nh my Kan Nam (Hn Quc), t hp cng nghip ng tu Singapore gii thiu. Nhng thng tin lin quan ti Vit Nam chng ti s dng ti liu ni b cng thng tin ca cc c s lm vt liu composite, ti thnh ph H Ch Minh, Nha Trang, Kin Giang. Mt s tnh nng k thut ca vt liu FRT nh sau: (1) Vt liu composite lm v tu thu gm nha polyester khng no, t l trng lng nha trong thnh phn vt liu t 70% n 50%. Vt liu ny thuc nhm nhit ho (thermoset), mi phn ng xy ra trong mi trng t nhin, nhit bnh thng (t chuyn mn cn gi l nhit trong phng). Thi gian ng cng vt liu sau khi trt c th t 5 pht, mt gi hoc lu hn tu thuc yu cu ngi ch to. Khc vt liu nha lm dng gia dng, FRP hn 40 tui th vn gi uc c tnh c hc tt xp x lc mi c. c trng chnh v c tnh cc vt liu tham gia vo composite FRT nh sau: (a) Vt liu si thu tinh. Trong thc t sn xut vt liu composite, nuc ngoi ngi ta ang s dng 6 nhm thu tinh dng trong cng nghip vt liu composite. Thu tinh nhm E c dng rng ri nht, p dng cho nhiu lnh vc, gi khng cao. Thu tinh nhm A(alkali), nhm C( chu ho cht), c tnh c hc khc thu tinh nhm E khng nhiu, song gi cao hn. Thu tinh nhm S v nhm R p dng vo nhng trng hp i hi v sc bn rt cao nh my bay siu tc, tu v tr, c sn xut v a vo s dng song gi thnh cn qu cao. Thu tinh nhm E c ko thnh si ht sc mnh, ng knh tnh bng n v micron (k hiu bng 1:1.000.000m). V d mi si thu tinh dng lm tm v hng c ng knh ch bng 8 15 m. Nhiu loi thu tinh c bn li thnh b v cng mang tn gi si thu tinh. Nhng b nh nht gm 60 n 120 si mnh. c tnh c hc thu tinh nhm E: t trng 2,56; gii hn bn khi ko 3,4x105 N/m; modul n hi 27x106 N/m2. S thu tinh c b thnh cun, c p thnh tm hoc dt thnh tm. trong ngnh tu thu chng ta ang s dng cc dng bn thnh phm t si thu tinh nh sau: tm si v hng, vit tt CMS (chopped strand mat), si (rovings) do nhiu b si kt hp di dng ln hn, cun xon vv .. T si ngi ta dt thnh tm vi thu tinh, vit tt ca cm t ny l WR (woven roving), c chiu dy vi, trng lung tm trn mt din tch thay i, v d vi loi 300g/m2 hoc 600 hay 800g/m2. Trong thnh phn v tu lun c mt CMS vWR. Phn b lp, chn chiu dy cc lp vi, v cch trt lp tu thuc tnh nng v tu, tu thuc thit k v cng ngh ch to. 25

Ngoi si thu tinh, khi lm vt liu composite ngi ta cn dng si aramind hay cn gi l si Kevlar, nh hn si thu tinh song bn cao hn. Loi si th ba, si carbon khi ra i ch phc v ngnh hng khng, v tr song ngy nay tm thy ch ng dng trong v tu thu v gi vt liu gim nhiu ln so vi ngy u. Mt s tu nh, ch yu cho quc phng c lm bng kevlar hoc si cacbon. Si cacbon v si thch anh c cc nh khoa hc Nga tng hp, p dng trong cng nghip quc phng c kt qu, v hin nay vt liu ny ang c thm nhp vo cc ngnh khng phi quc phng nh h gi sn xut. Trong iu kin ca nc ta, si thu tinh nhm E c dng ph bin lm vt liu composite. Si nhm ny cho n nm 1996 u c nhp t nc ngoi, ch yu t i Loan, Hn Quc, Nht, Uc v Trung Quc. Gi vt liu ny lin tc h thp trong nhng nm qua. Mt khc kh nng sn xut si thu tinh trong nc, dng nguyn liu l ct trng trong nc, theo cng ngh nhp t ngoi l mt thc t. Ngun nguyn liu si thu tinh c th c nh gi l kh n nh trong iu kin hin nay. (b) Nha polyester khng no. sn xut v tu composite, ngoi si thu tinh cn cn nha cao phn t. Trc y ti Vit Nam nhiu ngi s dng epoxy, ch yu do Lin x (c) cung cp, lm vt liu lin kt v lm vt liu th composite. Do gi thnh nha epoxy cn cao, cn gi nha polyester thp nn nha polyester c s dng nhiu hn trong cng nghip sn xut vt liu composite. c tnh c hc ca nha polyester thay i tu thuc ng cp nha ang dng. Tnh cht c hc chung cho c nhm polyester nh sau: t trng 1,38; Gii hn bn 1,0x105 N/m2; modul n hi 11x106N/m2. Hin nay trn th trng c chng 25 n 30 chng loi mang tn gi polyester dng lm vt liu composite. Nhng m hiu nha quen thuc trn th trng Vit Nam, t quan st c th thy, c ngun t Bc u (an Mch, Nauy), t Uc, Hn Quc, Nht Bn V Trung Quc. Nha polyester khng no dng cho ngnh ng tu u phi c cc c quan ng Kim tu quc t th nghim v cp chng ch cng nhn cht lng m bo cho vic lm v tu. Theo cch phn loi ca c quan ng Kim, nha polyester khng no c chia ra cc nhm nh nha dng vo nhiu mc ch; nha c v tu; nha lm lp ph v tu, t chuyn mn gi l lp o ngoi b mt (gelcoat); nha chm chy lm xung cu sinh chu la; nha chu tc ng ca ho cht; nha chu du; nha lm kt; nha lm bn cha nc, cha du. Trong sn xut thc t chng ta s dng gn ht chng loi nha c ng Kim cp chng ch. Mi chng loi ph hp vi cng vic c ch nh. Tu thuc nc sn xut, m hng ho thng mi ca nha khc nhau song cht lng nha mi nhm phi m bo nhng yu cu ti thiu. Theo cch phn loi ang thnh hnh Chu u, m hiu nha c k hiu bng s, v d nha 873E l nha a mc ch, c kh nng ng cng nhanh (chng 15 pht); nha 876E l nha chuyn lm v tu hoc cng trnh trong mi trng nc bin; nha 849 c kh nng chu la; nha 844 chu c tc ng ca acid. Cng lm tng y nhim v, cng c kh nng chu la, chu acid song m hiu nha sn xut ti Hn Quc c m ho nh sau: G-3(BT), G-774(T,S,Y,P,), RF-2000SE, S-650, vv Tu thuc kh nng s dng, v iu ny c lin quan n m hiu nha, gi nha khng hon ton nh nhau. Chnh lch gi gi nha cht lng cao v polyester cht lng thp hn c khi n 50%. Mt iu ng quan tm cho nhng ngi lm v tu composite l ga nha polyester trn th gii ngy cng gim. Nh s h gi mua nguyn liu gm si thu tinh v nha polyester, gi vt t lm v tu gim theo. n gi mt v tu hon chnh lm bng vt liu composite trc y cao hn gi v tu c kch thc tng ng lm bng thp hoc g, hin nay gi v tu composite khng vt qu gi v thp. 26

Cng ngh lm v tu bng vt lu composite hin nay bao gm cc bc chnh nh sau:(1) Lm khun m (khun ci ) bng composite; (2) Chun b vt liu chng dnh tch khun khi c xong; (3) Trt lp gelcoat; (4) Trt cc vt liu composite theo qui trnh xc nh; (5) To cc chi tit gia cng dc hoc ngang; (6) To vch dc, vch ngang bng vt liu composite hoc vt liu khc; (7) lm boong; (8) Lin kt thng tng. Trong tt c cc bc, khu vt liu composite ng vai tr ti cn thit. Vt liu ny c to ra khi lin kt bn hai thnh phn chnh l nha polyester nu trn. Vt liu s ng cng nhit bnh thng vi s c mt ca cht ng cng hay cn gi l cht xc tin hay cht gia tc. Thi gian ng cng thng p dng khi trt v tu l trn di mt gi ng h. Kch thc v hnh dng vt th do vt liu composite to thnh b gii hn bi s c mt ca khun m. Sau ng cng, v tu nh hnh ng hnh mu m khun m hn nh. Khi thnh vt liu composite c tnh c hc ca FRP nh sau: Vt liu FRP c t trng t 1,551,7 t/m3 .So vi thp ng tu, t trng ca FRP ch bng 1/5 t trng ca thp (t trng thp ng tu 7,8 t/m3). Gii hn bn nm trong phm vi 1200 1600 kG/cm2.

(2) Gii hn bn ca vt liu FRP thp hn ca thp (bng 50%60% gii hn bn ca thp ng tu vi gii hn bn ca thp ng tu 2400 kG/cm2). Xt khi lng vt t cn a vo tu cng kch c v tnh nng, c th nhn thy tnh, nh t trng bn thn nh cn gii hn bn khng qu nh so vi thp, nn s lung vt t FRP s nh hn, cn dng thp khi lng thp tnh bng tn s ln hn (xem bng so snh di). Tnh cht ny cho php gim lng gin nc ca v tu bng FRP, v iu ny c li cho vic lm tng tc tu hoc gim cng sut my. (3) Vt liu FRP ra i 50 nm, ng dng trong ngnh ch to v tu trn 40 nm. Nhng v tu u tin ch to t gia nhng nm 40 ca th k XX, trn c s cng ngh thi by gi, cha tin tin, vn cn bn vng cho n ngy nay. T thc t cho thy vt liu FRP tm c ch ng dng tt v ph hp trong ngnh ng tu thu. Thc t cng cho thy vt liu FRP khng b thm thu, khng ngm nc (t l ngm nc ca vt liu nm trong gii hn 1/10.0000), khng b lo ho nhanh. Sinh vt bin khng c kh nng thm nhp v ph hoi loi vt liu ny. Nh tnh cht ny vic bo dng v tu FRP d dng hn nhiu so vi bo dng v thp, v g. Ngi ta c th bo dng v tu FRP, k c phn chm m khng cn ln , vo nu v cha b s c trm trng. Di y l bng so snh cc tnh nng ch yu gia thp, nhm, g, vt liu FRP. Trng lng trn mt m2 din tch v tu di 14m c tnh nh sau cho cc loi vt liu khc nhau, trong tnh c vt t lm cc np gia cng kt cu: Bng 1.13 Cc c trng Trng lng ring, (t/m3) Chiu dy v (tnh mm) Trng lng vt liu/m2 G 0,780,82 35 50kg Thp 7,8 5 56kg FRP 1,61,7 9-10 24kg XMLT 2,6 28 76kg

27

CHNG 2 H THNG KT CU THN TU1. H thng kt cu thn tu V tu dng chung nht c xt nh kt cu v c np cng. Ba khung gin kt cu t cc dm ngang, dm dc, lp bng tm, nh gii thiu c tn gi bng ting Anh panel grillage, ng vai tr cc khung chnh to v tu. l cc khung gin y, mang k hiu 1, khung gin mn 2 v khung gin boong 3 ca kt cu tu v kim loi (hnh 2.1).

Hnh 2.1

Cn c b tr cc c cu cng nh vai tr cc panel trong ngnh xy dng, ca cc khung va nu phn bit h thng kt cu tu. Hai h thng kt cu tu, h thng ngang (transverse framing) c cch sp xp panel nh ti hnh 2.2a, trong khong cch gia cc c cu cng t ngang tu ngn hn khong cch cng tn song t dc. Nu k hiu a khong cch gia cc panel t ngang, b khong cch gia hai panel t dc, du hiu phn bit h thng ngang s l: a < b Ngc li, trng hp a > b chng ta gp kt cu theo h thng dc (longitudinal framing), hnh 2.2b. Trng hp th ba, khong cch a gn bng b, cc panel c xp nh mng li u nhau chng ta gp trng hp kt cu trung gian nh hnh 2.2c.

Li

Mui

Hnh 2.2 H thng kt cu tu Trc khi tm hiu cc h thng kt cu bn c c th nh li cch gi tn cc c cu v chi tit trong thn tu. Thn tu (hull) dng kt cu v mng c gia cng dc v ngang, m bo tu ni trn nc v lm vic an ton trong cc ch khai thc. Thng l c th coi tu gm ba phn chnh, xt theo chiu dc nh phn li (aft end region) chim khong 30% chiu di tu, phn gia tu (midship region) chim 40% v phn mi (fore end region) chim phn cn li. Phn mt tu c hiu l phn thuc 0,1L tnh t mi mt tu. Trong ba phn ny ngi k s phi i su vo phn tch, tnh ton v hnh thnh kt cu c trng tng vng. Nhng kt cu ti phn ui hoc phn li nh va gi thng thng gm c kt cu vng li, sau vch ui (after peak structure), kt cu vm ui, sng li (sternframe, shaft brackets and bossings). 28

Khu vc gia i c quan tm ng mc. Cc kt cu c tm quan trng c bit gm lp tn bao, mt ct ngang tng ng ca thn tu v m un chng un ca mt ct, cc vch ngang, vch dc (bulkhead), y tu, boong. Vng trc ca tu gm nhng phn quan trng: sng mi (stem), boong mi, kt su (deep tanks), kt cu c trng khu vc trc vch chng va (fore peak structure). Theo chiu cao, nhng ngi tnh ton kt cu tip xc vi nhng kt cu chnh ca tu, tnh t di ln nh y tu (c th dng y n, y i) thng l b phn quan trng nht nh, nm di cng thn tu. Trong cm kt cu ny sng chnh tu (keel) phi c quan tm hng u v y l xng sng ca tu. Nu bn c cn nh cch gi ca ngi Trung Hoa rng y l long ct, tc xng sng ca rng, chng ta s thy cch coi trng ca nhng ngi quan tm n kt cu tu thuyn. Dn mn, cc vch, ct chng vv nh nhng thnh ng, tr ng lm cho tu cng vng. Boong hoc cc boong (decks) v kt cu boong lm nhng chc nng khc nhau, boong gia (tweendeck) lm ni cha hng, boong trn ng vai tr boong thi tit khng ch che ma nng cho tu m cn ng vai tr boong sc bn. Nhng chi tit chnh ca thn tu bn c lm quen trong phn ny c th tng kt ti hnh 2.3.

Hnh 2.3. Kt cu chnh thn tu Cc ghi ch trn hnh 2.3 mang ngha: 1- mi tu (bow), 2- boong mi (forecastle), 3- thng tng gia (middle supertructure), 4- bung li (wheel house), 5- booong li (poop deck), 6- vm li (stern), 7- be gi, be chn gi, mn gi (bulwark), 8- lan can, tay vn (rails), 9- tn mn (side plating), 10y (bottom), 11- ming hm hng (cargo hatch), 12, 13- thnh ming hm hng (hatch coaming), 14sng mi (stem), 15- l li (stern-post), 16- boong (upper deck), 17-ng hn dc ni tn v (seams), 18- ng hn ngang (butt). Thng tng ca tu (supperstructure) c b tr trn boong, c th hn trn boong mn kh. Chiu rng thng tng c th bng chiu rng tu ti khu vc t thng tng. Trng hp thng tng c cc vch bn khng trng vi chiu rng mp mn, khong cch gia vch v mp mn khng ln hn 4% chiu rng tu ti khu vc ang cp. Thng l cc thng tng phi l kt cu kn, cc l khot vch bn hoc vch trc/sau phi c phng tin ng m bo kn nc, chu c tc ng mi trng. phn bit r rng v chnh xc h thng kt cu cn thit xem xt k hn b tr cc c cu cng ca tu. Trn tu kt cu h thng ngang, gin y, gin mn v gin boong c t chc hon ton theo 29

ng cch thc nu: ngang, sn, x ngang boong t ti mi khong sn, ni vi nhau qua cc m. Hnh 2.4 m t mt ct ngang tu vn ti i bin theo h thng ngang c trng cho h thng kt cu ny.

Hnh 2.4. Kt cu mt ct ngang tu theo h thng ngang Cc ghi ch trn hnh 2.4 mang ngha sau: 1 x ngang boong (transverse beam), 2 sn (frame), 3 ngang y (floor), 4 sng ph y (side girder), 5 sng chnh y (center girder), 6 sng hng (margin plate), 7 tn y trn (tank top plating), 8 tn boong trn (upper deck plate), 9 tn boong ni khoang th hai (2nd deck plate), 10 tn boong ni khoang th ba (3rd deck plate), 11 - tm quy ming khoang hng (hatch side coaming), 12 - tn sng nm/tn gia y (plate keel), 13 m hng (tank side bracket), 14 tn mp boong (stringer plate), 15 tn mp mn (sheer strake), 16 m x ngang boong (beam bracket). Mt ct dc tu vi kt cu theo h thng ngang c trnh by ti hnh 2.5 tip theo.

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Hnh 2.5. H thng kt cu ngang tu vn ti Cc ghi ch trn hnh 2.5 c ngha: 1 cc boong (decks), 2 vch ngang (tranverse bulkheads), 3 sn thng (frames), 4 sn khe (web frames) ch c trong bung my, 5 x ngang boong (deck beams), 6 ngang y (floors), 7 sng dc mn (stringers), 8 - x dc boong (girders), 9 sng mi (stem), 10 sng li (stern frame). Trong h thng ny, kt cu y, mn v boong tun th y qui nh dnh cho h thng ngang. Khong sn tu nh th hin ti mt ct dc, lun nh hn khong cch ngn nht ca hai c cu dc gn nhau. C th lu bn c ngay t nhng dng u tin v kt cu, rng trn tu vn ti t chc theo h thng ngang cc sn tu c b tr theo cch hp l nht nhm m bo bn tu m khng lm mt i dung tch cn thit cha hng. Cc sn mang tn gi bng ting Anh Web ch b tr trong khu vc bung my, m bo bn cc b, trong khi trong cc hm hng ngi ta ch b tr sn thng, trnh b tr sn khe nhm gim thiu phn chim ch ca c cu. Ngc li, trong h thng kt cu dc, xut hin cc c cu dc thy r trong c ba khung gin va cp. Khong cch gia cc np dc ca y, mn, boong (bottom, side, deck longitudinals) kh nh, xp x bng khong sn. Khong cch gia cc c cu ngang trong h thng ny kh ln, thng t ba khong sn tr ln. Hnh nh thn tu theo h thng dc c trnh by ti hnh 2.6 nu r s khc bit trong b tr c cu so vi h thng va nu trc.

Hnh 2.6. Kt cu h thng dc dng cho tu du 31

Tn gi c cu trong bn v ny c hiu nh sau. 1 boong (deck), thng thng tu du ch mt boong, 2 vch ngang (tranverse bulkheads), 3 sn thng (side frames), 4 sn khe (web), 5 x ngang boong khe (deck transverse), 6 ngang y (floors), 7 vch dc (longitudinal bulkheads), 8 np dc boong (deck longitudinals), 9 x dc mn (stringers), 10 boong dng mi (forecastle), 11 boong lu li (poop). iu c th nhn xt, kt cu thc s mang c tnh ca h thng dc tri di trn phn ln tu. Cc khoang hng ti khu vc gia tu t chc hon ton theo nguyn tc ca h thng dc. Phn mi tu khng p dng 100% nguyn tc ny, phn li ngi ta c thay i trong cch b tr h thng. bn v phi cnh tu ch hng lng, kt cu theo h thng dc c trnh by tip ti hnh 2.7.

Hnh 2.7. H thng kt cu dc tu ch du Cc ghi ch trn hnh mang ngha: 1- sng chnh y (center girder); 2- tn sng nm (plate keel); 3- ngang y (floor); 4,12- sng ph y (side girder); 5- dm dc y (bottom longitudinal), 6,10, 13, 17, 19,21, 23, 32, 40,43- np gia cng (strut); 7- tn y ngoi (bottom plating); 8- vch dc (longitudinal bulkhead); 9- np dc vch (bulkhead stiffener); 11- sng ng vch dc (longitudinal bulkhead girder); 14- di tn hng (bilge strake);15- tn mn (side plating); 16- dm dc mn (stiffener);18- sn khe (web frame); 20- thanh x chng va (panting beam); 22, 27, 29, 41, 42- m lin kt (beam bracket); 24- di tn mp mn (sheer strake); 25- dm dc boong (deck longitudinal); 26- tn boong (upper deck); 28, 30- x ngang boong khe (strong beam); 31- sng boong (deck girder); 33- sng chnh boong (center deck girder); 34,38 - sng ng vch (vertical girder bukhead); 35- vch ngang 32

(transverse bulkhead); 36- np vch (bulkhead stiffener); 37- sng nm vch (horizontal girder bulkhead); 39- sng ng vch ngang (vertical bulkhead girder). H thng hn hp dng cho tu ch hng kh c minh ha ti hnh 2.8. Theo cch lm ti y, y tu kt cu hon ton theo h thng dc (longitudinally framed bottom), boong trn cng theo ng chun dng cho y. Trong khi dn mn tu khc vi hai bn ni hai u, kt cu theo h thng ngang. Boong gia t chc theo h thng ngang. Ti y chng ta cn hiu h thng hn hp mang ngha thc t v kt cu, t chc theo cch ny cc c cu chu ng sut mt cch hp l hn v bng cch c th tit kim vt liu lm v tu mt cch ng k. Cn ni r hn, b tr cc c cu nh ti hnh2.8 l xut ca vin s hn lm Shymanski thi Lin x cn tn ti.

Hnh 2.8.

H thng kt cu hn hp dng cho tu hng

Cc ghi ch trn hnh mang ngha: 1 x dc boong (ting Anh chnh thc E-E gi l deck girder), 2 tn boong (deck plating), 3 np dc boong (deck longitudinal), 4 x ngang boong (deck transverse), 5 m (beam knee), 6 sn (frame), 7 tn boong gia (tweendeck plating), 8 x ngang boong (beam), 9 tn mn (side plating), 10 m hng (bilge bracket), 11 ki (vertical keel), 12 dc (side girder), 13 np dc y (bottom longitudinal), 14 ngang c (solid floor), 15 y trong (tank top), 16 tn y (bottom plating), 17 vch ( bulkhead), 18 np vch (bulkhead stiffener), 19 ct chng (pillar). 33

2. H thng kt cu ngang H thng ngang c dng trong ngnh ng tu t rt sm, ch yu cho cc tu chiu di khng ln. Nhng tu v g hu nh ch to theo h thng ny. Tu v thp ra i, ban u tu cha phi c ln nn c theo c, theo kinh nghim lm tu g ngi ta s dng h thng ngang lm chun. u im ni bt ca h thng kt cu ngang l kh nng chu cc lc tc ng ngang, tc ng mang tnh cc b rt tt. Nu xt v sc bn cc b, nh chng ta quen trong [8], h thng khung ngang k t ngang, sn, x ngang c kh nng chu ti trng cc b hon ho. Ch to tu c kt cu theo h thng ngang thng n gin, chnh v vy nhng nh ng tu ngy trc rt a chung kt cu dng ny. iu c th ni thm, trn cc tu ch hng kh, kt cu theo h thng ny cho php b tr cc khoang hng gn, hp l, to nhiu thun li cho ngi dng, dung tch hm hng ln cn thit. H thng ngang p dng trn tu c nh hoc c trung bnh t r tnh u vit ca n. Chiu dy tn v khng nht thit phi qu dy nh c cu lm vic ca bn thn tu. Momen un chung ti nhng mt ct khu vc gia tu, t l vi chiu di tu khng qu ln, ng sut nn cc tm boong hoc y trong nhng trng hp ny khng t gi tr ng lo ngi, n nh tm trong h thng ngang vn nhy cm vi ng sut nn v cch b tr tm khng to ra s lo lng qu mc. Mt ct ngang tu vn ti i bin, t chc theo h thng ngang, ch to vo nhng nm su mi c dng nh ti hnh 2.9. Trn hnh, chng ta c nhn xt: tu c thit k hai boong, np hm hng cu trc bng cc tm np ri, dc khoang hng c gn cc tm lt ngang 13 bng g, cch lm ny ngy nay c bin th bng cc tm lt thp, gia cng lin vi qu trnh ng mi tu.

Hnh 2.9. Mt ct ngang tu vn ti kt cu theo h thng ngang Cc ghi ch tn hnh c gii thchnh sau: 1- Np ming khoang (hatch cover), 2- X ngang tho lp c (hatch beam), 3- thnh ming khoang (hatch coming), 4- tn mn chn sng (bulwark plate), 5tn boong trn (upper deck plating), 6- x ngang boong (deck transverse beam), 7- m x (beam bracket), 8- vch dc (line bukhead plating), 9- np vch (bukhead stiffener), 10- tn boong th hai/boong ni khoang (tweendeck plating), 11- sn kho (web frame), 12- sn thng (hold frame), 13- tm lt ngang 34

(horizontal sparring), 14- ct chng khoang (hold pillar), 15- tn y trn (inner bottom plating), 16- vn lt sn (bottom ceiling), 17- ngang c (solid foor), 18- ngangh/gim trng lng (open floor), 19sng chnh (center girder), 20- sng ph (side girder), 21- tn y (bottom plating), 22- tn mn (side plating). Cc tu c nh thng l kt cu theo h thng ngang. Hnh 2.10 trnh by mt trong nhng v d thng dng thng thy trn cc tu cng tc c nh, chy sng. y tu t chc theo h thng ngang, 60 x6 sng chnh cao 400mm, sn khe c quy cch ch T b tr xen ln sn thng c quy cch 130 x 4 L63x40x5 v c sng dc mn. X ngang boong c quy cch L56x36x4, boong thng tng cao 2200mm, tn vch dy 3mm.

Hnh 2.10. Kt cu tu c nh, theo h thng ngang Hnh 2.11 v 2.12 trnh by kt cu tu hai thn chy sng vi kt cu theo h thng ngang. im khc bit so vi thng l c nu ti phn trnh by h thng kt cu, trn tu ny sn khe c s dng c nhng khoang ngoi bung my, k c khoang ui v khoang mi. Cc sn khe lm tng bn khi chu tc ng cc b.

35

36 Hnh 2.11. Kt cu tu catamaran theo h thng ngang

Hnh 2.12. Kt cu mt ct ngang tu hai thn (catamaran) chy sng3. H thng kt cu dc

So vi h thng ngang, h thng dc s dng vo kt cu tu mun hn, k t khi tu v thp tm c ch ng vng. H thng dc lc u ng dng rng ri hn trn cc tu qun s sau mi chuyn sang tu dn s. Cng lao trong lnh vc ny cn k n nh ng tu ngi Anh Scott Russel. Theo xut Russel t nhng nm1852 n 1857 kt cu h thng dc c p dng cho tu Great Eastern, m u cho vic s dng h thng ny. Tuy nhin cn ni r, cc nh ng tu v cc c quan ng kim thi cha tin lm vo h thng ny nu khng ni h c thi mit th h thng dc. Nm 1910, tc 60 nm sau k t lc h thng dc vo tu, Lloyds Register of Shipping ca UK cn phi ghi vo giy kim tra v phn cp tu v thp kt cu theo h thng dc mt k hiu m ngy nay chng ta cn ngm ngi exp, vit tt t th nghim nhng li mang ngha cha th xong hoc r hn ang giai on th nghim. H thng dc dng cho cc tu c chiu di ln t r nhiu u vit. So vi h thng ngang, nu dng cho tu di, h thng ny c th gim n 15% nguyn liu lm v trong khi vn m bo bn dc tu. Kt cu dc thng l kt cu khe hiu theo ngha cng, vng khi chu lc bn ngoi tc ng, cn tin cy cao. Chng ta th xem li vi vn chung quanh n nh tm thp lm v tu thy cc u im ng pht huy ca h thng kt cu ny 1. T l thuyt tm, v c th thy rng, vi cc tm cng kch thc hn vo khung tu trong h thng dc s c n nh cao hn bn ln nu so vi tm t ngang trong h thng ngang. Gi tr bn va nu cp n gii hn ca ng sut Euler khi tnh cho tm dc v tm ngang. Cn iu ny na, cc dm dc (girder, stringer), np dc (longitudinal) c tham gia y vo thnh phn cu thnh mt ct ngang ca dm tng ng khi tnh momen qun tnh mt ct, m un chng un mt ct, trong khi cc chi tit quan trng hng u ca h thng ngang, v d ngang, sn, x ngang vv khng c mt trong cc bng tnh quan trng ny. iu sau cng gii thch rng mc du h thng dc phi s dng lng vt t ng k lm cc c cu tng cng nh nu trn song tnh chung cuc lng vt t a vo thn tu di vn t hn nu so vi kt cu theo h thng ngang. ng dng h thng dc trn cc tu vn ti c th thy r qua cc v d. Tu vn ti hng kh, c ln, chiu di tu di, chu tc ng momen un chung s mang ga tr ln. Trong cc kt cu chnh to nn thn tu, tm y v tm boong nm xa trc trung ha nht.1

ngh bn c xem thm phn L thuyt n hi.

37

Ti hai nhm kt cu ny ngi ta phi x l ng sut nn nhiu khi t gi tr nguy him cho n nh tm. Tnh hnh ny i hi y v boong c thit k theo h thng dc, cc tm c b tr theo cch c li nht v mt m bo n nh. Tu hng phi c cc ming hm hng rng, di nhm tng tnh thun li bc d hng , rt ngn thi gian thao tc hng. Tu hin i thng b tr t mt dy n nhiu dy ming hm hng, v nh vy chiu rng l khet ti tm boong rt ln. Hu qu ca vic lm ny l di tn cn lin tc ca boong, di tn c php tham gia vo thnh phn mt ct ngang dm tng ng cn li khng nhiu. Ngi thit k b bt buc phi tng cng cc np dc, cc kt cu dc khc lm tng din tch boong trong thnh phn mt ct ngang dm tng ng v tng momen qun tnh cng m un chng un ca mt ct. iu ny gii thch tu vn ti c ln c thit k theo h thng dc l chnh. Kt cu c bn tu hai thn chy sng, t chc theo h thng dc c gii thiu ti hnh 2.13 v 2.14. H thng dc ca tu b tr theo thng l nhm m bo bn chung ton tu trong cc ch khai thc. Kt cu ngang trong tu c tng cng vi mc ng k so vi cc tu chy sng mt thn nhm m bo bn cc b tu. Kt cu y v mn khu vc bung my theo h thng ngang nhm tng cng bn cc b. Mt ct ngang tu, hnh 2.13, trnh by thm chi tit, sn tu ti thng tng t chc trong h thng ngang, tm che trn cng c dp sng chy dc tng cng dc, t boong tr xung kt cu tu theo h thng dc.

Hnh 2.13. Mt ct ngang catamaran trong h thng kt cu dc

38

Hnh 2.14 H thng kt cu dc tu catamaran

39

4. H thng hn hp ngang dc

H thng hn hp dng ph bin cho tu vn ti c ln thng t chc theo m hnh nu ti hnh 2.15.

Hnh 2.15a

Hnh 2.15b40

Cc ghi ch trn hnh 2.15a v 2.15b mang ngha: 1- sng chnh (center girder), 2- sng ph (side girder), 3- dm dc y di (bottom longgitudinal), 4- dm dc y trn (top longgitudinal of double bottom), 5- ngang c (solid foor), 6- di tn gia y (keel), 7- di tn A/k di tn gia y (A strake), 8- tn y (bottom plating), 9- di tn hng (bilge strake), 10- tn mn (side plating), 11- di tn nh mn (top side strake), 12- di tn mp mn (sheer strake), 13- tn y trn (inner bottom plating), 14m hng (tank side bracket), 15- tm p (gusset plate), 16- sn khoang (hold frame), 17- sn ni boong (tween deck frame), 18- x ngang boong th hai (2nd deck beam), 19- m x (beam bracket), 20- boong th hai (2nd deck), 21- boong trn (upper deck), 22- tm mp boong (stringer plate), 23- m chng vn (tripping plate), 24- x ngang boong (deck transverse beam), 25- dm dc boong (deck longitudinal), 26sng boong (deck girder), 27- thnh ming khoang (hatch coming), 28- x ngang boong kho (strong beam), 29- sn kho (web frame), 30- ct chng khoang (hold pillar), 31- ct chng boong ni khoang (tween deck pillar), 32- tn mn chn sng (bulwark plate), 33- tay vn (hand rail), 34- ct np mn chn sng (bulwark stay), 35- np nm (horizontal bracket), 36- vy gim lc (bilge keel), 37- m gia cng sng chnh (docking bracket), 38- m gia cng sng hng (bracket to margin plate), 39- m hng (tank side bracket), 40- m lin kt dm dc y (bracket to longgitudinal bottom), 41- np ng (vetical stiffener), 42- thanh chng (strut), 43- l khot cho ng hn chui qua (scallop or serration), 44- l khot gim trng lng (lightening hole), 45- sng hng nghing (margin plate), 46- l khot ngi chui (manhole), 47- vch kn nc (water tight bukhead), 48- np vch (bukhead stiffener), 49- tm m chn ct chng (doubling). ng dng thc t ca m hnh c gii thiu ti hnh 2.16 di y. Trong y tu t chc theo h thng dc vi cc c cu gm np dc y L200x100x10, t cch nhau 900. dc chnh (ki ng) chy sut khu vc gia tu 0,4L cao 1160mm dy 13mm. dc ph b tr i xng qua tm dc tu, mi bn hai dc. hai boong u t chc theo h thng dc. Cc khung khe ca h thng ngang t cch nhau 3,0m. X ngang boong trn c chiu cao tm thnh 350, chiu cao cho x ngang boong gia 380. Sn khe b tr ti khu vc bung my, cch nhau 3,0m. C cu sn khe t thp m 340x12,5.

Hnh 2.16 H thng kt cu hn hp dng trn tu hng41

H thng kt cu hn hp cn c ch ng trn cc tu ch du c trung hoc c ln. Bn v phi cnh miu t h thng hn hp ngang dc trn tu du c trnh by ti hnh 2.17.

Hnh 2.17 Trn hnh c th thy r, kt du dc p dng ng nguyn tc cho gin y, gin boong. Gin mn tu t chc theo nguyn tc h thng ngang. Hai vch dc ca tu vi t cch thnh phn chnh tham gia bn dc tu, c tng cng bng cc c cu t chc trong h thng ngang. Cc np ng lm t thp nh hnh lm chc nng c cu cng, hn vo vch nh sn tu vo mn. Hai u np ng ngi ta s dng m ln, b mp, lin kt np ng vi tn boong v tm y. Chiu rng chn m di, ting Anh vit l bracket, phi vn n np dc y gn n nht. Chiu cao bracket thng phi t 1,5 n 2 ln chiu rng. M lin kt u trn thng c kch thc nh hn. Bn v k thut mt ct ngang cng tu c trnh by hnh 2.18 sau:

Hnh 2.18. Mt ct ngang tu ch du42

5. Kt cu cc tu vn ti thng dng

Trong phn tm hiu h thng kt cu ny bn c c th tm hiu k kt cu cc tu trong nhm tu ch hng tng hp (general cargo ships) tu du (tankers), tu ch hng ri (bulkcarries), tu ch qung (ore carries), tu ch hng thng (container ships), nhng tu c kt cu theo h thng ngang v/hoc h thng dc. 5.1. Tu vn ti hng kh. Tu nhm ny c gi chung l tu ch hng tng hp, ng gi hoc cu kin, l tu ra i sm, s lng ng o nht. Tu vn ti i bin sc ch t 7.000 dwt n trn 10.000 dwt, tu cn hi (ven b) sc ch khim tn hn, t vi trm tn n 1.500 dwt. Mt s kiu tu vn ti hng kh ra i khong nhng nm nm mi tr v sau c gii thiu ti chng 1, mc 1.1.

Hnh 2.19 Tng chiu rng cc ming hm hng so vi chiu rng tu vt qu gii hn cho php ca nhng nm gia th k XX. T l ny ngy nay c th t n 80% - 85%, hnh 2.19. Ngoi tnh trng trn y, nhng tu chuyn ch hng kch thc ln, kh a ln tu qua ming hm hng trn boong ngi ta phi m cc ming hm hng ti mn. S lng l khet ny c khi t con s khng nh. Cc l khot lm cho kt cu mn b yu, hnh 2.20.

Hnh 2.20 c im kt cu tu hng c ln cn ch, s boong trn tu khng ch mt m thng c thm cc boong gia. Kt cu c trng ca tu c ln trong nhm l tu ba boong, bn c nhiu ln lm quen trong ti liu ny. Hai hnh va nu trn l tu ba boong, tnh theo chiu cao. Trong mi trng hp vi tu ming hm hng rng nht thit phi tm mi bin php tng din tch phn tn lin tc nm ti boong, tham gia vo thnh phn mt ct dm tng ng, tng m un chng un ca mt ct. Thnh ming hm hng (hatch coaming) cc tu ang cp phi ch to theo yu cu b p bn cho boong b khet. Kt cu thnh ming hm hng tu vn ti v vy thng c kch thc khng thng thng, chiu dy tm thnh khng nh v kt cu ny chy dc, lin tc trn sut chiu di phn gia tu. Mt s tu trong nhm tm kim bin php tng bn dc qua kt cu y i, mn i.43

Chia khoang tu vn ti theo qui tc chung, cc vch ngang, kn nc c b tr cch nhau khng qu 0,2 chiu di tu. Nhng nm cui th k XX chiu di gia hai vch ngang k nhau trn cc tu vn ti chy nhanh nh cc liner ships tu vn ti trn cc tuyn ng di, c nh, tu ch hng lnh, b thu ngn hn nhm tng tnh chng chm. y i tu p dng trn cc tu khng phi tu c nh. Tu di t 60 m tr ln u c y i, chy lin tc t vch chng va mi n vch khoang li. Chiu cao y i c chiu cao ti thiu 620 mm ngi c th kim tra, thao tc cc cng vic cn thit trong hm y i. Chiu cao y i thng gp ca tu hng kh t 1,0m n 1,20m. Khong khng trong y c s dng cho nhiu mc ch, ngoi chc nng khoang chng chm. Trong y i c th b tr kt cha nc dn, nu cn phi th, cha du, nc cho tu. Kt cu c trng tu vn ti c nh, thm ch c trung bnh l kt cu theo h thng ngang. Mt ct ngang tu gii thiu ti hnh 2.4, hnh 2.9 i din cho kt cu ny. Cn ni r thm, h thng ngang p dng cho c tu vn ti hng kh vi lng chim nc trn 20.000 dwt. Tu vn ti vi chiu di kh ln thng c kt cu thuc h thng hn hp ngang dc. Mt trong nhng v d kt cu hn hp c trnh by ti hnh 2.15. Mt ct ngang qua khu vc khoang hng gia tu ca tu vn ti i bin, ch hng kh thuc nhm general cargo vi b tr nhiu tng boong c nu ti hnh 2.21. Kt cu y v boong chnh tu theo h thng dc. ngang, x ngang boong chnh ti cng hnh c b tr cch ba khong sn. Sng boong kt cu dng hp nhm gia tng tit din mt ct ngang b p cho phn din tch boong b khot l ln. Mn tu v tweendeck t chc theo h thng ngang. Kt cu c bit nh nu ti hnh ra i khong nhng nm su mi, t ta hu hiu trong khai thc. Hnh 2.22 tip theo trnh by b tr chung ca tu. Tu dnh 5 khoang hng trc bung my ch hng general tng hp. Hm hng 1 b tr trn kt dn, ko n boong mi. Khoang hng 2 c 2 tweendeck. Cc khoang 3, 4, 5 s tweendeck tng ln 3. Khoang hng lnh t sau bung my. Np hm hng b tr thun tin cho vic bc d hng tng khoang hng. Khu vc gia tu, ti cc hm hng 4 v 5 b tr hai dy np hm hng. Khoang hng 1, 2, 3 b tr mt dy np hm. Np cc khoang hng lnh b tr thnh ba dy nh trnh by ti hnh.44

Hnh 2.21. Mt ct ngang tu vn ti nhiu boong

Hnh 2.22. B tr chung tu vn ti thuc nhm general cargo5.2. Tu ch du

Tu ch du hin i thng l c kt cu theo h thng dc ti khu vc gia tu, ni b tr cc khoang hng, cn khu vc mi tu, li tu h thng chuyn sang ngang. Nh cp trong phn bn v h thng ngang, khu vc mi tu, li tu chu tc ng momen un chung vi gi tr khng cao song tc ng ti trng cc b khng nh. Tu nhm ny phong ph v kch c. Tu du sc ch ch vi trm tn chy sng hoc ven bin xut hin t th k trc XX. Nhng nm by mi th gii chng kin s pht trin rm r i tu du khng l, gi l voi ma mt trn bin, sc ch c na triu tn. Tu du sc ch mt triu tn c thit k song ngi ta khng ch to v nhng l do kinh t.45

Kt cu tu hng lng, trong c tu ch du, ph thuc nhiu vo loi hng c ch trong . Nhng im chung ca kt cu tu nhm ny l tu mt boong v thng l boong bng. Tu c chia khoang theo qui tc cht ch nhm tng tnh chng chm. Ngoi cc vch ngang nh tu hng kh vn c, tu du thng c t mt n hai, thm ch ba vch dc tu, hnh 2.23. Hnh 2.23 c im khc ca tu du ng hn chc nm v trc l vng bng y i k c trong tu kch thc v cng ln. Ming hm hng tu du rt nh, ch phuc v vic cho ng ng i qua v l ch vo, ra khoang hng cho ngi kim tra hm hng. Din tch ming hm hng ca tu ch du, k c nhng tu khng l cng khong chng 1m2. Tuy nhin, kch thc ming hm phi cho php mt ngi c eo thit b dng kh v thit b bo v chui ln hoc xung cu thang m khng b cn tr. Chiu cao thnh ming hm ch t 0,3m n 0,75m. Nhn hng vo tu v a hng ra khi tu hon ton nh vo h thng bm hng cng h thng ng ng. Nhng c im do qu trnh khai thc gy ra vi tu du c th k thm sau y. Cc khoang hng thng rng v di, cht lng di chuyn trong khoang khng ch gy ra thay i trng tm hng m cn nh hng ln n n nh do hiu ng mt thong. nh hng tnh do dch chuyn hng ny n bn kt cu khng nh, nh hng ng do hin tng sloshing kh ln n kt cu boong, vch khoang hng. Hng lng trong tu thay i th tch theo nhit , do vy cc khoang cha hng lng phi c dung tch cho s thay i th tch kh v cht lng. Tu vn ti hng kh t gp tnh trng chy di ballast nu cng tc chun b hng hai u bn tin hnh bnh thng. Ngc li i tu ch hng lng lun phi tnh n kh nng ch ch hng mt chiu, chiu ngc li phi chy theo ch di ballast. Tnh trng khai thc nh vy s nh hng n bn cc kt cu trn tu. B tr chung ca tu du thng thng nh sau. Bung my tu nm sau, thng tng b tr trn khu vc bung my. Khoang bm hoc khoang cch ly ngn cch bung my vi cc khoang hng. Cc khoang hng, theo chiu dc b cc vch ngang kn nc, kn du ngn cch. Khong cch gia cc vch ngang khng qu 15m. S liu thng k cho thy, chiu di khoang hng khng qu 0,12 chiu di tu. Kt cu c trng ca tu du l h thng kt dc. Trong h thng ny cc gin y, mn v boong t chc theo h thng dc ng ngha. Cc vch dc ca tu chy qua sut cc hm hng, tham gia vo thnh phn cc kt cu tng cng bn chung. Cc khung khe gm ngang, sn khe, x ngang boong khe nm cch nhau chng 3m 4m. Phn li, k c bung my tu, thng l chuyn sang h thng kt cu ngang nhm tng cng bn cc b. Phn mi tu cng thng thit k v ch to trong khun kh h thng kt cu ngang. Chng ta th xem xt k hn mt phn on thn tu trong khu vc gia tu, qua cc khoang hng, t chc trong khun kh h thng dc, hnh 2.24. Trong h thng ny nhng chi tit c trng ca thn tu gm: 1 - cc np dc y (bottom longitudinals), 16 dc gia (bottom centre line web), 3 - dc y (bottom girder), 6 np dc mn (side longitudinals) , 7 np dc boong (deck longitudinals), 8,9 - sng dc boong (deck webs), 4 np dc vch (bulkhead longitudinals) v 10 sng dc boong (deck centre line girder). Nhng thnh phn tng cng bn ngang, bn cc b gm: 2 46

ngang y (bottom tranverse), 5 sn khe (vertical tranverse web), 11 - x ngang boong khe (deck transverse web).

Hnh 2.24 Tu ch du c nh, chy sng c mt ct ngang nh trnh by ti hnh 2.25.

Hnh 2.25. Mt ct ngang tu du c nh, chy sng.47

Mt ct ngang tu du c trung bnh vi cc chi tit va nu c th hin trn bn v k thut c gii thiu ti hnh 2.26.

Hnh 2.26. Kt cu theo h thng dc ca tu du Ngy nay tu du phi c thit k v ng theo nhng yu cu khc khe nhm trnh tnh trng trn du ra bin khi s c. Yu cu tu phi c y i, tu y i mn i c hiu lc t nhng nm tm mi. Tu thn i (theo cch vit ca ngi Anh: double hull) khng ch c y i nh chng ta quen trn tu hng kh, m cn i lin vi mn i. Khong khng gian trong thn i ny c s dng a mc ch. Cc khoang c th dng cha ballast, nhin liu v nc ngt. Trong nhiu trng hp li i c m ngay trong khu vc mn i. Hnh 2.27 gii thiu mt ct ngang tu y i, mn i c trung bnh. Chiu cao y i bng chiu rng trong mn kp, bng 1200mm. Li i bn trong xuyn qua cc vch phn vch i dc gia tu. Tu c thit k theo h thng kt cu dc cho c y, mn v boong.48

Hnh 2.27. Mt ct ngang tu du thn kp double hull Kt cu thn kp (double hull) tu du c tnh bt buc vi tu sc ch ln hn gii hn xc nh bng lut ng tu. Mn kp ca tu du c th khng cn b tr trn tu sc ch di 5000 dwt v mi dung tch khoang hng khng qu 700m3. y i khng bt buc vi tu du sc ch 5000dwt hoc hn nu tha mn nhng iu kin khc khe qui nh ring cho tu du, s c bn tip sau y. Tu du sc ch di 600 tn deadweight c php khng s dng y i, mn i. y i tu phi m bo dung tch cn thit do vy chiu cao y i khng c php di mc qui nh. Chiu cao y i tnh bng B/15 (m) hoc 2,0m, chn gi tr b hn, song trong mi trng hp khng c php nh hn 1,0m, vi tu c sc ch hn 5000 dwt. Chiu cao thp nht p dng cho tu c sc ch 600 < DWT < 5000 s l 0,76m. DWT (m) hoc b = 2,0 (m), chn gi tr b khi 20000 tnh. Tuy nhin yu cu bt buc, chiu rng ny trong mi trng hp khng c php nh hn 1,0m. 2,4 DWT (m) Trng hp tu c sc ch 600 < DWT < 5000 chiu rng tnh theo cng thc: b = 0,4 + 20000 hoc 0,76 (m), chn gi tr b trong tnh ton. Chiu rng mn i tnh theo cch : b = 0,5 +

Kt cu hn hp theo h thng dc v h thng ngang khng ch dng trong tu hng kh m cn tm thy ch ng trong tu du. Mt ct ngang miu t kt cu hn hp ca tu ch du 13.500DWT ng trong nhng nm gn y c trnh by trn hnh 2.28 tip theo. Hnh 2.28a m t kt cu mt ct ngang khung sn thng cn hnh 2.28b m t kt cu mt ct ngang khung sn khe.49

Hnh 2.28a. Mt ct ngang khung sn thng tu du 13.500DWT Trn hnh ta thy, tu s dng kt cu thn kp ph hp vi lut ng tu ngy nay. y i ti dc tm tu cao 1400, ra ngoi mn ct ln cao 1600, khong cch gia mn trong v mn ngoi l 1200. Boong, y v mn trong kt cu theo h thng dc, mn ngoi kt cu theo h thng ngang. Khong cch gia cc dm c cu l 600. Tu s dng kt cu sng chnh y dng hp, khong cch gia hai tm sng chnh y bng chnh chiu cao sng hnh thang ca kt cu vch dc, cn di tn sng nm rng 1500, dy 15,5mm. Tn y ngoi 11,5mm; tn y trong 13mm; tn mn 14mm; tn hng 11,5mm; tn boong 11,5mm. Dm c cu ca cc dn s dng thp m, quy cch dm c cu nh sau: dm dc boong 200x11,5; dm dc mn trong 220x10; dm dc y trn 260x11; dm dc y ngoi 240x10; sn thng 200x11.

50

Hnh 2.28b. Mt ct ngang khung sn khe tu du 13.500DWT H thng hn hp dng trong tu du ven bin c trnh by ti hnh 2.29. M hnh dng ny cn c dng ph bin cho tu du chy sng.

Hnh 2.29. Mt ct gia tu du ven bin, c nh51

c tnh chung kt cu cc tu du nh cp, khu vc t bung my v sau v khu vc pha mi h thng kt cu dc khng xm nhp vo hoc xm nhp c mc . Trong hai vng ang cp kt cu tu ch yu tun th qui nh ca h thng ngang. nhng i hi t ra cho nhng nh thit k khi x l kt cu tu du l m bo tnh lin tc ca bn thn kt cu ti khu vc qu t h thng dc sang h thng ngang. Ni cch khc, phi dnh u tin cho s lin tc cc c cu dc nhm m bo bn chung ca tu. Trong thc t chng ta c th thy, gi tr momen un tu ti khu vc cui tu b gim ng k nu so vi gi tr momen un tnh cho khu vc gia tu. iu ny cho php ngi thit k tm cch gim dn s tham gia ca c cu dc trong khu vc ny, min rng cng vic xy ra hi ha, khng gy s xo trn t ngt. Hnh 2.29 gii thiu hai mt ct tu qua khu vc bung my tu ch du i bin, c trung bnh. H thng kt cu dng ti y mang c trng h thng ngang. Cc c cu dc ca h thng dc tu sau khi i sut cc khoang hng cn c tip tc di cc hnh thc tha ng. Sn trong khu vc bung my t ngang mc m sng dc mn (stringer) ang chim gi v nh vy c cu kho ny vn tip tc cho n ht phm vi bung my. Cc sng dc mn khc c ko di cho n vm ui ca tu. Cc c cu khc thuc h thng kt cu ngang thit k yu cu m bo bn cc b m yu cu ny thng rt cao i vi bung my tu. B my trong khu vc ny c kt cu cng vng nh cc b my trong tu vn ti bin bt k no.

Hnh 2.29. Mt ct ngang qua bung my tu du52

Cch lm khc dng trong kt cu khu vc mi v khu vc li tu du l tun th cch b tr ca h thng dc. Hnh 2.30 trnh by mt ct ngang qua khu vc bung my tu du i bin, b tr c cu trong h thng kt cu dc. Trong trng hp ny cc np dc ko di sut t mi n li. iu cn bn ti y, y i ca tu trong vng ny cn c gii quyt theo cch thch ng, khng nht thit phi tun th cc qui nh ca h thng kt cu dc mt cch cng nhc. Khong khng trong y i ti vng ny c chia ra cc vng cha du d tr, nht, nc vv do vy phi c qui hoch theo cch hp l nht. H thng kt cu ngang dng cho vng ny to nhiu thun li hn cho cc cng vic. Ngoi iu ra, yu cu m bo bn cc b ti y phi c t ln v tr cao; h thng kt cu ngang nh chng ta bn n, lm vic ny tt hn.

Hnh 2.3053

5.3. Tu ch hng ri

Tu ch hng ri dng ch hng ha th ht, ch qung hoc vt liu tng t, cha ng gi. Hng thng c cht ng trong qu trnh bo qun v c khi chuyn ch. Trong ting Anh t bulk c dng ch hng loi ny. Trong trng hp ny hng bulk nn c hiu hng cht ng, hng khi (s lng) ln vv Tu ny c gi chung l tu ch hng ri bulk carrier trong ting Anh hoc Massengutschiff nu dng ting c . Nhng mt hng thng gp trong nhm hng ny l qung kim loi, khng kim loi, than , ht ng cc, mt s loi ha cht, ct, xi mng vvHnh 2.31 gii thiu s b tr tu ch qung lp Panamax.

Hnh 2.31 Tu ch hng ri c pht trin theo hai hng chnh. Hng th nht tp trung chuyn mn ha tu c ch to. Theo hng ny tu ch ch mt mt hng, khai thc theo nhng tuyn ng c hoch nh. Trong qu kh c nhng tu ch dng ch qung (tu ch qung), tu ch than , tu ch xi mng, tu ch ng vvTu ch qung: c tnh ni bt ca mt hng ch bng tu ny l trng lng ring ca qung ln hoc rt ln. Mt khc cc vn chuyn qung thp hn rt nhiu nu so vi vn chuyn mt hng khc. Hai iu trn i hi ngi thit k phi c cch x l, tu ch qung kt cu khng qu phc tp, cu k, song tu phi to mi thun li cho vic thao tc bc d hng, ln hng. Tu phi bn, c bn chung v bn cc b, m bo tu an ton trong qu trnh khai thc.

Nhng i hi kht khe va nu a n kt cc kh hp dn, kt cu tu ch qung lun c dng bt thng nu so vi tu vn ti bt k m chng ta gp. Hnh 2.32 trnh by ba mt ct ngang tu ch qung tiu biu. Hnh 2.32a gii thiu tu ch qung xp x 60.000dwt, hnh 2.32b dnh cho tu 24.200dwt v hnh th ba trong nhm dnh cho tu 18.900dwt.54

Hnh 2.32. Mt ct ngang tu ch qung Mt ct dc tu ch qung tiu biu c gii thiu ti hnh 2.33 sau.

Hnh 2.33. Mt ct dc tu ch qung Hng th hai tp trung x l nhng vn k thut to ra nhng tu ch c nhiu mt hng. Trong hng ny ngi ta ch to nhng tu kt hp dng ch nhng mt hng khc khc nhau trong cc chuyn i v v. V d, tu ch qung khi i song lc v thay v chy ballasst tu c th ch than. Mt hng ca tu dng ny bao gm t hng ri, hng kh n hng lng. Bng k di y trnh by dung tch ring , tnh bng m3/t cho mt s mt hng dng trn cc tu ch hng ri ni chung v tu kt hp ni ring. Qung st 0,25 0,85 Boc xit 0,72 - 1,0 Phot phat 0,7 1,2 Than 1,10 1,65 Ng cc (nng) 1,13 1,45 Ng cc (nh) 1,50 2,2 Xi mng 0,70 - 0,75 ng 0,90 1,30 Trong hng ny ngi ta cn to ra lot tu tng hp (hoc hiu theo cch khc, tu vn nng). Tn gi tu ny c th l tu ch hng ri tng hp - Universal Bulk Carrier (UBC) hoc Universal Bulk Ship, vit tt UBS. Tu ny dng ch hng dng bulk cho c chuyn i v c chuyn v. Tu ch hng ri c ng c ln trung bnh, tnh bng DWT nm trong bng tng kt sau. Tu ch du th 60.000 Tu ch qung 40.000 Tu tng hp 32.000 Tu ch bc xt 16.600 Tu ch than 4.000 Vn tc khai thc ca i tu ny khng qu 14 16 Hl/h. Tu chy chm trong nhm thuc tu ch than, xi mng, vn tc ch vo khong 11,0 11,5 Hl/h. Tu tng hp c khi chy nhanh hn 16Hl/h. Hnh 2.34 gii thiu tu ch hng ri a nng (UBC) loi ang c ng v khai thc ph bin nht hin nay, lp Diamond 53 (53.000 DWT), hin ang c ng hng lot t nm 2003 ti cc xng ng tu Trung Quc v Vit Nam. Hnh 2.35 gii thiu mt ct ngang cng tu.55

56 Hnh 2.34. Tu ch hng ri a nng (UBC) 53.000 DWT /DIAMOND 53

Hnh 2.35. Mt ct ngang tu hng ri 53.000DWT (Diamand 53)

57

Tu ch du-qung. Mt trong nhng tu kt hp cng vic c nhng nh ng tu thit k u tin l tu ch du trong chuyn i v qung chuyn v (ting Anh: Combination Vessels). Nhn chung kt cu tu ch qung du, gi tt l tu O-O (Ore-Oil carrier), khng khc tu ch qung, ting Anh ch gi Ore carrier, gii thiu trn hnh 2.36. im khc nhau chnh ng thi l du hiu phn bit tu O v O-O l trn tu ch mt hng du nht thit c bung bm v h thng bm hng. Ngoi ra tu O-O cn c h thng thot kh do du, cc khoang cch ly gia hnh lang, khoang hng mn.

Hnh 2.36. S b tr tu O-O Sn phm du vn chuyn trong tu dng ny c t trng trong gii hn 0,80 0,90 t/m3, tng ng h s dung tch ch hng ca tu 1,10 1,25 m3/t. T y c th thy iu cn suy tnh l dung tch cn cho vic cha hng nh, trong trng hp ny l sn phm t du, s gp hai ln dung tch cn cho hng nng. Hng lng trn tu O-O cha trong cc kt b tr trong cc khoang mn hoc y i, trong cc kt mt ct ngang dng ch L, cc deeptank vv B tr bung bm v s lng bm trn tu O-O nhm m bo bm hng, gm nhn hng, chuyn hng n v tr tp kt trong hn nh chun. Thng thng thi gian bm hng khong 10 12 gi.

Hnh 2.3758

Hnh 2.37 trnh by b tr tu O-O deadweight 44.500t c ch to v s dng c hiu qu. Ghi ch trn hnh mang ngha: 1 - kt hng, 2 kt ballast, 3 kt d tr tu, 4 bung bm, 5 kho. Sn phm t du c cha trong cc kt ti cc vng nh du bng 2, 3, 5, 6. Qung ch c b tr trong vng 1 v 4. T cc hnh va trnh by c th nhn xt chung v tu nhm ny nh sau. y l nhm tu mt boong, b tr bung my pha li, y i, mn i. y i ca tu ny c chiu cao qu c, mn i, nu c, thnh thong cng qu c. Chiu di khoang hng di hn tu nhm khc. Vi tu ch qung l mt hng nng, dung tch hm hng khng i phi ln nht m ch mc va . Thng l chng ta thit k tu ch qung theo yu cu v dung tch ring hm hng trong gii hn = 0,50 0,60 m3/t. Cn ni thm, nhng nm cui th k XX kh nhiu tu trong nhm c dung tch ring dnh cho hm hng t n gi tr 0,70 0,85 m3/t. Dung tch hm hng thc t ca tu c tnh sau khi loi tr dung tch mn i v y i trong khu vc ny. Cng thc kinh nghim xc nh chiu rng hm hng bhh (chiu rng tu tr hai ln chiu rng khoang mn) v chiu cao y i tu ch qung hdd nh sau:bhh h = 0,50 0,60 ; dd = 0,25 0,30 B H

Dung tch cc khoang mn, y i dng cho vic cha d tr v ballast. iu khc thng na, ballast cn c cha ti cc kt trn chng ta lm quen. Cc kt trn tuy dung tch khng ln song lng ballast ti y gip cho vic ko trng tm tu ln cao trong cc ch khai thc. Cn ni li cho r, vi tu vn ti thng dng hoc tu du chng ta tm mi cch h thp trng tm tu nhm tng kh nng n nh. Ngc li vi tu ch qung, tnh th thng o ngc, vi hng nng, trng tm tu thng nm thp lm cho chiu cao tm nghing ca tu tng nhiu nu so vi tu thng thng. Vi tu c GM ln qu c nh chng ta quen gi trong phn l thuyt tu, tu s cng qu. Tu cng s lc vi bin khng nh song chu k lc qu ngn, tnh m ca tu khng cn, an ton ca tu kh m bo. Cu hnh mt ct ngang tu ch hng ri c trnh by ti hnh 2.38. Cc ghi ch mang ngha: 1 l trng cho hng (opening with portable plate), 2 tm chn cnh (side panel), 3 ti hng ht (grain), 4 boong dng (raised quarter deck), 5 li i (passage). Mt trong nhng c tnh thuc kt cu tu ch qung cn l li i trong tu, b tr di boong. y khng ging ng hm (tunnel) m l li i (passage) hay cn gi l hnh lang, cho php ngi i t li n mi v ngc li trong mi iu kin thi tit bn ngoi tr nn xu. T hnh lang ny c li thot ra ngoi v cng c c li dn ra khoang mn, n y i. Li i b ngn thnh tng on nh cc ca ra vo. Ti vch kn nc nht thit phi b tr ca kn nc. Hnh 2.38. Mt ngang in hnh tu hng ri59

Tu ch hng lng v hng ri: H tu ch hng lng hng ri kh a dng, tuy nhin khng khc nhiu so vi tu tng hp trnh by. Nhng yu cu b sung cho tu lm nhim v kt hp thng dnh cho hng lng, c th hn cho cc sn phm t du. Cc tu u tin ca nhm ny ra i t nhng nm su mi v ngy cng pht trin kiu cch, mu m. Tu ch hng kt hp du-hng ri-qung: Tu nhm ny c vit bng ting Anh Oil-Bulk-Ore Carrier, vit tt OBO carrier, c kt cu a dng (hnh 2.39).

Hnh 2.39. S b tr tu OBO Kh khn ln khi gii quyt nhng vn thit k kt cu tu ch hng kt hp l tm gii php dung ha cho hai kt cu tiu biu nu tip ti hnh 2.40. Kt cu bn tri dng cho tu ch hng ri chnh hiu (Bulk carrier), hnh bn phi l kt cu c trng ca tu ch qung (Ore carrier), c v cng t l.

Hnh 2.40. Mt ct ngang tu Bulk carrier (a) v Ore carrier (b)60

Kt cu c trng ca tu ch hng ri (bulk carrier) c th thy trn hnh 2.41 trnh by sau y. Tu y i vi chiu cao y kh cao, c trng hp n 6m. y trong thng t bng sut c chiu rng tu. Tm y trong c hn c nh vi tm mn v c lin kt vi tm mn qua m hng (bracket). Kch thc m hng thng rt ln. c im th hai ca kt cu ny l, kt thng (top tank) c kch thc kh ln, dung tch ln dng vo hai vic khc nhau: hoc cha nc dn hoc dng cha hng. Hng c a vo kt qua h thng ming hm hng din tch kh nh trn boong.

Hnh 2.41. Mt ct ngang tu hng ri c kt cu hn hp Kt cu tu thuc kiu kt cu hn hp ngang dc. Cc np dc y, dc boong b tr theo cch quen thuc nh vn dng cho cc tu vn ti khc theo h thng kt cu dc. H thng cc sn m bo bn cc b khng khc nhiu nu so vi tu vn ti hng kh. Tu vi kt cu kiu ny dng vo vic vn chuyn than, ht nng v cc hng nng khc ch trong hm hng, v hng ht nh va trong khoang hng va trong kt thng. Khi ch hng nng trong khoang, cc kt thng cha nc dn nhm nng cao trng tm tu, bng cch h thp chiu cao tm nghing ban u GM0, gim lc ngang cho tu. Bin php chng tu cng ny c p dng cho tu ch hng nng, m bo tnh m v m bo an ton cho tu. Kt cu v vai tr tm nghing trong tu ch hng ri a dng. Vch nghing ti hng (hopperside) b tr di nhng gc xc nh, to thun li cho qu trnh bc d hng v bo qun hng trong vn chuyn. Vi tu ch hng nng, vch hng hn ch dung tch phn di ca khoang, bt buc hng phi dn ln cao, trng tm hng nng theo. Hng ri theo trin dc ca vch nghing xung vng tp kt nhanh hn khi bc d hng. vch nghing pha trn lm nhim v chnh l nn che st mt thong hng ht khi ch hng y khoang. Vch nghing thit k ph hp vi dc t nhin ca ngn hng c tc dng ngn dch chuyn mt thong hng. Kt cu ca vch nghing gii thiu ti hnh 2.42.

61

Hnh 2.42a. S b tr kt cu tu hm hng Bulk carrier Nhng chi tit chnh ghi trn hnh 2.42 mang ngha sau: 1- Sn khoang (side shell frame), 2Ranh gii ca vch ngang v vch nghing (boundaries of transverse bulhkeads and bukhead stools), 3boong ngang (cross deck), 4- Thnh quy ming hm hng (hatch coaming), 5- Sn ngang trong kt ballast (hopper side transverse), 6- tn y trn (inner bottom plating). hiu r hn b tr ny, hnh 2.42b gii thiu mt ct ngang cng hnh.

Hnh 2.42b. mt ct ngang in hnh hm hng Bulk carrier62

Mt cch tng t, hnh 2.43 nu di y trnh by y kt cu vch nghing hng lm chc nng thnh kt hng v vch nghing trn lm chc nng y kt thng trong tu ch qung kiu c.

Hnh 2.43

Hnh 2.44

iu c th ni thm, kt cu cc khoang ny theo h thng ngang trong trng hp c th ny. Li i trn tu ny b tr khong gia hai kt nc dn ang nu. Trng hp tu c hai vch dc, b tr vch nghing hng v vch nghing trn nh ti hnh 2.44. Trng hp sau chng ta c th thy rng li i c t cao, ng vo v tr top tank m cc tu khc vn thc hin. Tu ch qung c cp v gii thiu ti cc hnh 2.32, 2.40b c kt cu thc s phc tp. Kt cu theo h thng dc p dng trit cho y, mn, boong v cc vch dc, khng k vch ng hay nghing. Qung thuc nhm hng t trng ln cn c quan tm lc cht hng trng tm hng nm cao nht trong iu kin c th. Khoang cha qung c dung tch khng ln, nm cao. Chnh v l chiu cao y i tu t con s chng mt nh nu. Vch dc tu kin c, nm rt gn mt dc gia tu. Vch nghing phn vch di thay cho vch nghing hng nu trn, hn ch lan rng ca qung ti y trong, vch nghing phn trn ca vch ngn dch chuyn qung ti mt thong. Hnh 2.45. Kt cu tu ch qung bn cc b phi c xem xt k v c bin php x l thch hp trn tu ch qung. H thng khung sn kho, hay ni hn, rt kho, m nhn chc nng sau. Hnh 2.45 trnh by trong bn v63

phi cnh kt cu tu ch qung. Nhng chi tit chnh ghi trn hnh mang ngha sau: Ki chnh hay cn gi sng chnh, ki ng mang s 1, cn 2 khoang cha qung, 3 li i v 4 kt ballast. Hnh 2.46 tip theo trnh by bn v mt ct ngang tu chuyn dng trong lnh vc chng ta ang quan tm.

Hnh 2.46. Kt cu mt ct ngang tu ch qung Tu O-O nhc ti phn di y c kt cu gn ging m hnh va cp ti hnh 2.46. c trng ca tu nhm ny, tu mt boong, hai vch dc, y i cao, hnh 2.47.

Hnh 2.47 Mt hng th nht, t ch O u c xut x t Ore, c xp ti khoang trung tm, b ngn bng hai vch dc bn. Trng hp ny tu lm vic khng khc tu ch qung. Mt hng O th hai, Oil du, ch trong cc kt hnh L b tr ti cc khoang mn v y i. Trn hnh 2.47 k hiu 2 ch cc kt dng L dng cha hng (oil - du), 3 qung (ore).64

Mt ct ngang c trng ca tu O-O gii thiu pha phi hnh 2.47. C th nhn thy r, kt cu tu O-O theo h thng dc. H thng cc thanh ging lun phi c mt nhm tng cng bn cc b. Tu UBC trnh by ti hnh 2.34 cng cc mt ct ngang ph bin ti hnh 2.35 l hnh mu ca nhm tu bulk carrier hin i. Tu khng ch ch mt loi hng duy nht m phi ch kt hp, ch nhiu loi hng tnh nng khc nhau. im khc ca tu ang trnh by l h thng cc boong gia (tweendeck) c b tr xen k trong cc khoang hng ca tu. Hnh nh b tr tweendeck nh minh ha ti hnh 2.38e. Tu chng ta ang xem xt, chiu dc chia thnh 5 khoang hng di, b tr ba cm tweendeck mn. Vch dc khng ton phn, hiu theo ngha, vch khng gn chn vo sn y, khng ko di lin tc sut chiu di nh nhng vch chng ta gp trong tu du, cho php to nhiu khoang hng mang tnh c o. Theo m hnh 2.38e, khng gian b vch dc v tweendeck ngn nm ti v tr cao, thun tin cha hng ht hoc nc dn. Trng hp s dng cc khoang ang nu cha hng ht, khoang di cha qung chng ta c tu ch t nht hai loi hng. Ngoi khu vc tweendeck khng ton phn vch dc thay i kt cu. Thng thng vch dc h thp phn chn n ngang tm sng dc mn (stringer) hoc su hn song khng chm y, hnh 2.38g v 2.38f. Cc vch ny c th coi l vch treo, lun b hng chn. Vch hng chn kiu ny c tc dng rt tt ngn nh mt thong ti ngn cht hng ht ti khoang tu, trong khi cho php hng tun t cc khoang mn vo dy khoang gia. Bin php ngn nh hng mt thong nh th ny t ra rt hiu nghim. Trng hp sau cho php s dng tu vo vic ch hng ri t trng khng cao trong tt c cc khoang hng. S cht hng ca hng Mc Gregor p dng cho tu UBC ang cp c dng nh ti hnh 2.48. Trn s ti hnh 2.48 phn bit cc loi hng sau: a) qung nng, dung tch ring hm hng: 0,45 m3 /t; b) than , dung tch ring hm hng: 1,33 m3 /t; c) ht nng, dung tch ring hm hng: 1,25 m3 /t; d) ht nh, dung tch ring hm hng: 1,56 m3 /t; hnh 2.48e dnh ring cho trng hp chy di ballast.

Hnh 2.48

Hnh 2.49 cho s ng hng v vai tr ca cc kt trong vng khoang hng ca qu trnh chuyn ch hng ho65

Hnh 2.495.4. Tu ch hng thng tiu chun (container).

Thng tiu chun c xut t rt sm, trc nhng nm nm mi. n nhng nm su mi thng tiu chun c thng nht ho v c dng trn khp th gii. Thng (container) kch thc LxBxH tnh bng n v feet (20x8x8) c thng nht l n v chun dng cho tu container. Mt n v thng di 20 t trn tu gi l TEU (Tweenty feet Equivalent Unit). Nm 1964 t chc quc t v tiu chun ha IOS (International Organization for Standarnization) thng nht a ra tiu chun cho cc thng dng vn chuyn hng ha trn tu thy. Cc thng ny c kch thc o trong h metric, theo qui nh mang tn gi tiu chun ISO nh sau:66

Kiu Di IA IB IC ID IE IF IIA IIB IIC

Kch thc ph b, (m) Rng Cao 2,44 2,44 2,44 2,44 2,44 2,44 2,3 2,1 2,30 2,44 2,44 2,44 2,44 2,44 2,44 2,1 2,1 2,1

NHM I

NHM II

12,20 9,15 6,10 3,05 2,04 1,52 2,92 2,40 1,45

Trng lng ti a, t 30,5 25,4 20,3 10,2 7,1 5,1 7,1 7,1 7,1

Thng nhm I c chiu rng v chiu cao cng mt c 8 (tng ng 2,44m trong tiu chun ISO), thng nhm II c chiu cao cng c 2,10m. Trng lng ti a ghi trong tiu chun tnh n lng hng trong thng. Hnh nh thng container c tham kho trn hnh 2.50 di y:

Hnh 2.50 Cng c vn chuyn container trong vn ti bin l tu ch container (container ship), bao gm: Tu ch hng bch ho (General Cargo Ship): ch yu ch hng bch ho thng thng, nhng trong mi chuyn c th nhn ch mt s lng hn ch container xp trn boong. Tu bn container (Semi-Container Ships): thng c ci to t cc tu hng bch ho, trn tu c vi hm tu thch ng cha container v mt s container c xp trn boong. S hm hng cn li ch hng bao gi thng thng. Tu container kiu t ong (Full Cellular container ships): loi ny c cu trc mt boong, chia lm nhiu hm, c nhiu vch ngn, trong mi hm c th xp 7 8 tng container. Trn boong cng c cu trc c bit c th xp c khong 40% tng s container. Tu container kiu RO-RO: loi tu ny c cu trc nhiu boong, gia cc boong c cc ng dc nghing, c b tr mi, ui, hoc bn mn tu c ca xp d container. Phng php xp d67

theo phng nm ngang (phng tin ln Roll on and Roll off). Theo cch ny, container c trn xe r moc, t hoc toa xe mt phng, ri c u my ko a thng vo hm tu. cng n, li dng u my ko a thng container cng r moc, toa xe t hm ln b. Tu container kiu LASH (Light Aboard Ships): l loi tu c cu trc c bit, c trang b cn cu khung c sc nng 500 1500 tn xp d s lan. Sc ch moi s lan t 100 1000 tn. Trn mi s lan c th xp hng ho thng thng hoc xp container c cha hng (gi l s lan container Light container ship). Cc s lan c xp ln tu m (Mother Ships). Mt ct ngang qua hnh 2.51 di y nu r cch sp xp thng trong tu Semi-Container c ng vo u thp nin su mi ca th k XX. Tu c thit k y, boong the h thng dc, mn the h thng ngang vi 02 sng dc mn. im c bit l tu c thit k li i t thng tng li ti thng tng mi trong hm boong.

Hnh 2.51. S xp thng tu Semi-Container. Tu ch container tiu chun c cc khoang hng hnh khi, cha nhiu dy v nhiu chng thng. Tu dng ang nu c th gi l tu (ch) ch container, tng ng cch gi ca ngi Anh Full Container Ship hoc cch gi ca ngi c Vollkontainerschiff. hnh 2.52 di y nu r cch sp xp thng trong tu full-Container. Kt cu trong khoang tu ch hng thng tiu chun khc tu ch hng kh thng thng ch, trn cc thnh ng ca khoang hng phi lp t cc thanh dn hng thng. Cc thanh ny lm hai chc nng ng thi: gip y nhanh qu trnh a thng vo, ly thng ra v ngn cn x dch thng khi68

tu chuyn ng. Thng gp trn cc tu ang khai thc cc thanh dn hng lm t thp hnh c 100x100 hoc 150x150 mm, hnh 2.53 m t vic b tr cc thanh dn hng thng nh vy.

Hnh 2.52. S xp thng tu full container

Hnh 2.58. B tr ray dn hng Thng l, bung my tu container t pha sau. Thng tng tu b tr li pha sau bung my. iu khc thng ca tu hng thng cng th hin ti khu vc ny. Trn mt phn boong l thin trn khu vc bung my v boong l thin vng khoang hng, ngi ta ln sn cng vng cht thng cao ln. Tu ch container c ln, sc ch 1700TEU c gii thiu ti hnh 2.53. iu cn c quan tm c bit khi thit k tu kiu ny l b tr cc khoang hng cha s thng nh v kt cu phi m bo bn khi ch thng tiu chun. Ti liu trch t thit k tu container trn c th tham kho khi thit k kt cu tu kiu ny. Tu mang cp ng kim c (GL CLASS 100 A5) vi chiu di ton b LOA = 184,10m; chiu di gia hai tr Lpp =171,94m, chiu rng B = 25,30m, chiu cao mn D = 13,50m, chiu chm d = 9,50m, lng chim nc = 23.000 tn, trang b my chnh c cng sut 13320 KW, d tnh khai thc vi vn tc v = 19,7 Hl/h. Tu mt boong, bn khoang hng. Bung my tu t pha li. Tu c thit k ch thng tiu chun 20 (TEU) theo chun ISO, kiu IC song c th ch thng 40 (FEU) kiu IA ca ISO. Sc ch ca tu 1730 TEU. Trong s thng ny 634 TEU b tr trong cc khoang, 1096 TEU (chim ~ 64%) b tr trn boong.69

70 Hnh 2.54. B tr chung tu container 1700TEU

Hnh 2.54. B tr thng tu container 1700TEU

71

Vic b tr cc thng container nh sau: phn gia tu ngi ta sp container thnh 8 hng ngang, trn ming hm hng b tr mi hng container, theo chiu dc v chiu cao tin hnh b tr cc hng v chng theo s trn hnh 2.54. Mt iu ht sc lu trong qu trnh b tr thng l kt cu khng gian vng mi nhm va m bo b tr hp l thng trong hm va bn kt cu cho khng gian vn cht hp v chu ti trng lm vic nng n , v vn ny, bn c c th tham kho c nhiu iu t s b tr thng hnh trn. Mt ct ngang in hnh ca tu container c gii thiu ti hnh 2.55 tip theo, mt ct ngang khe vng gia tu th hin trn hnh 2.55a, mt ct ngang thng vng gia tu th hin trn hnh 2.55b.

Hnh 2.54a. Mt ct ngang khung sn khe tu container 564TEU y i tu cao 1400mm. Mn i ca tu c chiu rng mi mn ti vng gia tu l 1600mm. Kt cu y, boong, mn trong tu theo h thng dc, mn ngoi theo h thng ngang. Chiu dy tn t v ngoi 11mm, tn y trong 16mm v tn mn trong 13mm. Cc dm dc boong s dng thp bn 200x20, cn dm dc y, dm dc mn trong v sn mn s dng thp m ln lt c quy cch cho mn ngoi 180x9; mn trong 180x8; y trong 260x10; y ngoi 220x10. Thanh dn hng t ng bng thp gc 130 x 130 x 12 (mm).72

Hnh 2.54b. Mt ct ngang khung sn thng tu container 564TEU Tip theo, trn hnh 2.55 bn c c th tham kho mt ct ngang ca cng tu k trn ti vng mi, y, mt ln na lu v b tr khng gian xp thng trong hm v phng n kt cu cho vng ny. Tu ch hng thng pht trin khng ch s lng m c v ln trong vi mi nm gn y. Cng vi s i thay kch c, kt cu tu cng phi i thay nhm m bo bn tu ming hm hng m qu rng, trong khi vn phi m bo thao tc xp thng tin hnh nhanh nht nhm gii phng hng ngn thng trong thi gian rt hn ch. Hin nay i tu container chim khong 14% v trng ti v 18% v s tu ca i tu bun th gii. Phn ln tu container c ng v khai thc t nhng nm 70 ca th k XX, sc cha trung bnh ca tu container t 1200 TEU (1989); 1500 TEU (1993) v vn c xu hng tng ln. Tu container bc sang th h th 4 v sc ch ngy cng ln, c th vi tu trn hnh 2.53 c ng ti Vit Nam nm 2005 vi sc ch 1700TEU.

73

74 Hnh 2.55. Mt ct ngang khung sn vng mi tu container 564TEU

5.5. Tu ch kh ha lng (Liquid Gas Carriers) Tu ch kh ho lng thuc nhm tu vn ti ch kh ha lng trong tu, thc cht l cc bnh chu p lc cao trong iu kin nhit h thp n mc cn thit. Ngoi tu ch kh gc du cn c tu ch kh t nhin. Kiu th nht dnh cho tu ch kh t cng nghip du kh, sau ha lng (liquefied petroleum gas LPG), kiu sau dnh ch kh t nhin ha lng (liquefied natural gas LNG). LPG l tn gi c xut x t cng nghip du kh, ch chung cho nhm kh trong cng nghip ny l hydrocarbon , ch yu gm propane v butane v c kh pha trn ca chng. Kh ny c th ha lng v vn chuyn chuyn theo mt trong ba cch:

Di p sut thng v nhit mi trng, Lm lnh hon ton n nhit si, t -30C n -48C, Lm lnh bn phn n nhit xc nh v p lc cao.

Mt s kh khc nh ammonia, propylen v ethylene cng c th ch bng tu tu ch kh kiu ny.LNG l kh t nhin c loi b lu hunh v carbon dioxide. Cn thit lm lnh kh n nhit si ca n, vo khong -165C. p lc gi kh ho lng ny c th ch bng hoc gn nh p sut kh quyn. Trong nhm ny vn chuyn methane lng i hi phi tha mn nhng yu cu ring ca n. c tnh ca methane nh chng ta bit, c p lc gii hn 45,6 kG/cm2 v nhit gii hn 82,5C, iu ny c ngha methane ch c th ha lng di p lc ln, nhit v cng thp.

Tu ch kh kiu u c vit bng ting Anh Liquefied Petroleum Gas Ship c phn loi theo kt cu cc khoang ch hng. hn 2.000m3 . Tu dng ch ch yu propane, butane cha trong cc bnh tr , t hai n 6 bnh, t hon ton hoc khng hon ton di boong. Cc bnh ny c thit k chu p lc n 17,5 kG/cm2. p lc ny gn trng vi vi p lc bc hi ca propane ti nhit 45C.

Khoang hng chu p lc (fully pressured tanks). Dung tch cc tu ny thng khng ln

Khoang hng nn bn phn (mt na) hoc lm lnh bn phn (semi-pressured or semirefrigerated tanks). Dung tch tu nhm ny ln n 5.000m3. Cc bnh trn tu c thit k chu c nhit -5C v p lc ln nht khong 8 kG/cm2. Pha ngoi bnh c cch nhit. Hng trong tu c lm lnh v bo qun ti p lc tnh ton.Khoang lnh (fully-refrigerated tanks). Dung tch tu nhm th ba ny c th t 10.000 m3 n 100.000 m3. Tu dung tch nh trong nhm thng l tu dng ch nhiu mt hng, tu ln thuc tu chuyn dng cho mt mt hng. Tu ch kh t nhin (Liquefied Natural Gas Ship) c thit k v ch to theo nhng chun nht nh. Trong thi gian qua nhng nh ng tu ng k hn 20 sng ch cho thit k tu LNG, phn ng trong thuc v nhm kt cu mng mng (membrane category) hoc kt cu c lp (independent category). Theo khuyn co ca t chc hng hi quc t IMO ghi trong Internatinal Gas Carrier Code trn tu ch kh c th s dng cc kt cu dng sau.

Kt lin hay bnh kh lin (integral tanks), theo ngha cc khoang hng tu vn ti c kt cu lin thn tu chng ta quen trong cc chng trc, c dng ch LPG ti p lc kh quyn hoc gn nh vy. Kt mng mng (membrane tanks) thuc kt cu tu, lm t cc lp vt liu (gi l membrane) ta trn cc tm cch nhit, cn cc tm cch nhit l chi tit thuc kt cu thn tu. Kt mng mng ch yu dng cho tu LNG.75

Tu ch kh ha lng v cc kiu dng c trng trnh by ti hnh 2.56. Trn hnh gii thiu tm tu a vo s dng trong thp nin su mi, thit k v ng ti: Germany (a), Nht bn (b, c, h), Php (d), Na-uy (f), Thy in (g). Chiu di cc tu nu ti y nh sau: tu c nh Ultrgas L = 22,6m, hnh 2.56a; tu L.P. Maru No 2, hnh 2.56b, L = 47m; tu Nordphone v Petrogas, hnh 2.56d, 2.56e L = 100m; tu Mundagas Brasilia, hnh 2.56f, L = 119,5m; tu Paul Endakott, hnh 2.56g, L = 167,6m.a) e)

b) c)

f)

g) d) h)

Hnh 2.63 Kt cu khoang ch hng cho tu ch kh ha lng thc hin theo cch trnh by nh hnh 2.64 sau. Hnh 2.64a trnh by s mt ct ngang tu thuc nhm gas tanker, hnh 2.64b gii thiu mt ct ngang cng tu nhm ny song mang tn gi c trng bng ting Anh gas carrier, ng dng trnh by ti 2.63b, c, d. C th phn bit k chi tit hn vi tn gi gn lin vi tu ch kh ha lng ny. Hnh 2.64c gii thiu kt cu mang tn Kvaerner-Moss, ng dng ca n th hin trn s 2.63f, hnh 2.64d trnh by h thng membrane dng rt nhiu trong nhm. Hnh 2.64c) a)

b) d)

H

B tr tu ch kh methane ha lng trnh by ti hnh 2.65. Kt cu c trng tu nhm ny c gii thiu ti hnh 2.66.76

Hnh 2.65. Tu ch kh methane ha lng

Hnh 2.66. Kt cu c trng tu ch kh methane ho lng77

5.6. Tu khch Khc vi cc kiu tu chng ta ang xem xt c v b tr v kt cu, trong nhm tu khch ngi ta phn bit tu i bin thng c ch to vi kch thc ln, tin nghi y vi tu chy ni a gm tu sng, tu trong vnh. Tu khch ni a thng c kch thc nh, hoc c s dng ch khch chy chuyn tuyn (tu ch) hoc ch khch du lch. B tr ca cc tu ni a nhn chung kh n gin do thi gian hnh trnh ngn. Kt cu ca tu thng thng theo h thng kt cu ngang. Hnh 2.67 gii thiu cc chi tit cu trc ca tu khch hng ven bin thuc loi ny, trong hnh 2.67a gii thiu cc chi tit tng th, cn hnh 2.67b m t kt cu y.

b)

Hnh 2.67. Chi tit cu trc tu khch hng ven bin Cc ghi ch trn hnh 2.67 c ngha: a) phn tng th (general view): 1- chn vt (propeller); 2sng ui (stern frame); 3- bnh li (rudder); 4- xung cng tc (tender); 5- cu xung (boat davit); 6- n ui (stern light); 8- cu neo (anchor davit); 9- soma (fair-lead); 10- sn xc t (quadrant grating); 11- ct buc/bt (bollard); 12- thng gi hnh nm (mushroom ventilator); 13- trng ti qun dy (wire reel); 14ct chnh (main mast); 15- ng khi nh bp (funnel of galley); 16- kt v sinh (sanitary tank); 17- ca tri bung my (engine room skylight); 18- ng khi (funnel); 19- ng thng gi mt k