Gio trnh

K thut ng tu

LI NI U

Cng vi s pht trin ca t nc,cng nghip ng tu ca nc ta c

nhng bc i mang tnh cht t ph:m bo cung cp cc con tu hng 6500 DWT,12100 DWT ...cho cc cng ty vn ti trong nc ,ch to cc con tu 53.000 DWT xut khu . phc v cho cc bc pht trin ,vic gio dc o to nng cao trnh ca i ng cn b ng tu t ra rt khn thit ,trong c vic nng cao trnh ngoi ng phc v vic hi nhp ,giao lu vi ton b th gii ng tu rng ln.Trc tnh hnh ,nhm Vn Phong chng ti ch trng bin son mt lot sch phc v cng nghip ng tu v hng hi ,trong c cun sch u tin Ting Anh K Thut ng Tu.Cun sch ny vit theo kiu gio trnh gm 30 bi ,bm st trnh t ng tu k t thit k,lp rp v tu,lp my.trang thit b .trang b in ,thit b hng hi ..ti khi th tu v bn giao ,k c vic lm hp ng ng mi ...Vi mc ch h tr cho vic t hc,cc bi hc u c mc gii ngha t mi ,ch gii cc thnh ng v cc vn ng php kh cn quan tm .Cui mi bi l bi dch sang ting Vit tham kho v cui sch c bng vocabulary t kim tra vn t hc.K thut ng tu c trnh by trong cun sch l nhng vn mi nht,c a cc thc t sn xut hin nay ti cc nh my thuc Tng Cng Ty Cng Nghip ng Tu Vit Nam Vinashin .Bi vy cun sch ny c th dng lm ti liu ging dy nng cao nghip v hin nay,lm ti liu ging dy ti cc trng V ni dung k thut c cc tc gi bn ng Anh vit d hiu nh mt ti liu ph bin k thut ,nn cun sch cng cn l mt ti liu tham kho rng ri cho tt c nhng ai quan tm ti cng nghip ng tu v hng hi nc nh .Ti y,chng ti xin php c trn trng cm n b Linda Davis thuc SNAME v b Trng Bo Ngc trng i hc Cng trnh Harbin trong vic cung cp ti liu thc hin cun sch ny.

Qung Ninh ngy 15 thng 11 nm 2005 Nhm Vn Phong Ch bin: Thi Bnh

Contents Ni dung

Lesson 1-Principal Dimensions Bi 1- Cc kch thc ch yu Lesson 2-Other Seakeeping Performances (1) Bi 2-Cc c tnh hng hi khc(1) Lesson 3-Other Seakeeping Performances(2) Bi 3-Cc c tnh hng hi khc (2) Lesson 4 Hull Construction(1) Bi 4-Cu trc thn tu (1) Lesson 5- Hull Construction(2) Bi 5-Cu trc thn tu(2) Lesson 6 Ship Equipment Bi 6-Trang b tu Lesson 7-Workmanship for Hull Building(1) Bi 7-Cng ngh ng tu (1)

Lesson 8-Workmanship for Hull Building(2) Bi 8-Cng ngh ng tu (2) Lesson 9-Welding Bi 9-Hn Lesson 10-Marine Diesel Engines (1) Bi 10-ng c disel tu thy(1) Lesson 11-Marine Diesel Engines (2) Bi 11-ng c diesel t uthy(2) Lesson 12-Marine Diesel Engines (3) Bi 12-ng c diesel tu thy (3) Lesson 13-The Propulsion Plant Bi 13-Trang b y tu Lesson 14- The Shaft System Bi 14-H thng trc Lesson 15-The power systems of Diesel Engine Bi 15-H thng ng lc ca ng c diesel Lesson16- Ship Systems (1) Bi 16-H thng tu (1) Lesson 17-Ship Systems (2) Bi 17-H thng tu(2) Lesson18-The Power System Bi 18-H thng in Lesson19- The Application of Electricity on Board Bi 19-p dng in trn tu Lesson 20-Three Stages of Main Engine Control Bi 20-Ba giai on kim tra my chnh Lesson 21- Power Station Automation Bi 21-T ng ho trm in Lesson 22- Navigation Equipment Bi 22-Thit b o hng(dn ng) Lesson 23- Radio Communication Equipment-GMDSS Bi 23- Trang thit b lin lc v tuyn-GMDSS Lesson 24- Painting Bi 24-Sn Lesson 25- Sea Trial Bi 25-Th trn bin Lesson 26-Quality Management Bi 26-Qun l cht lng Lesson 27-The Application of Computers Bi 27-p dng my tnh Lesson 28-Shipbuilding Contract (1) Bi 28-Hp ng ng tu (1) Lesson 29-Shipbuilding Contract (2) Bi 29-Hp ng ng tu (2) Lesson 30-A promising year of shipbuilding Bi 30-Mt nm y ha hn ca ngnh ng tu

T sch VN PHONG

T sch mang tn nh nho Vn Phong (1860-1930),mt lnh t ng Kinh Ngha Thc vng Phc Yn , b thc dn Php bt i y ti Guyane Nam M ,sau vt ngc ,tr v hot ng ti Nam B cng vi cc nh nho khc nh V Honh,Nguyn Quang Diu... Vn Phong ch trng nh Mai Lnh mong mun ng gp vo s nghip vn ho gio dc ca t nc. Cc sch v s xut bn: 1/Ting Anh -K thut ng tu Sch dy 320 trang 2/ K thut ng tu hin i-Song ng Anh-Vit. Sch dy 400 trang ,song ng Anh Vit ,gm cc bi c chn lc t cc bi vit mang tnh ph cp ngh nghip ca cc t chc c uy tn nh Hi cc K S ng Tu v Hng Hi SNAME ca M,RINA ca Anh ,Bch Khoa ton th Britanica 3/S Tay Cng Ngh ng Tu 4/Bch Khoa ng Tu v Hng Hi

Qung Ninh ngy 15 thng 11 nm 2005 Knh gi Ban Gim c Nh Xut Bn Giao Thng,

Trc tnh hnh thc t pht trin ca Cng nghip ng tu nc ta, nhu cu hc hi ting Anh ngy cng tng,chng ti bin san cun : Ting Anh-K THUT NG TU 1/Ni dung cun sch: (xem li ni u km theo)

Cun sch ny vit theo kiu gio trnh gm 30 bi ,bm st trnh t ng tu k t thit k,lp rp v tu,lp my.trang thit b .trang b in ,thit b hng hi ..ti khi th tu v bn giao ,k c vic lm hp ng ng mi ...Vi mc ch h tr cho vic t hc,cc bi hc u c mc gii ngha t mi ,ch gii cc thnh ng v cc vn ng php kh cn quan tm .Cui mi bi l bi dch sang ting Vit tham kho v cui sch c bng vocabulary t kim tra vn t hc.K thut ng tu c trnh by trong cun sch l nhng vn mi nht,c a cc thc t sn xut hin nay ti cc nh my thuc Tng Cng Ty Cng Nghip Tu thy Vinashin. 2/ i tng s dng:

-sinh vin ,hc sinh cc trng -cn b trong ngnh ng tu v hng hi -ng o bn c quan tm ti ng tu v hng hi

3/ Trnh by Sch in trn giy tt kh 10,5x21cm,tng s khong 320 trang ,ba couch c in hnh mu thiu n v con tu Vinashin .S lng 500 cun 4/Thi gian pht hnh Vo gia thng 2 nm 2006 ,cho mng Hi ch VietShip 03 ti H Ni Mong kin ca Nh Xut Bn Trn trng THI BNH

Lesson 1-Principal Dimensions If you turn up a technical specification which is regarded as the code of

shipbuilding, you will always find that Main Group 1 in the index is Ship General. Normally speaking, contents under Ship General will, in spite of some slight differences among individual specifications, include general description, materials, dimensions and tonnage, stability, classification, drawings, supervision, tests and trials, delivery, etc. In this little passage, however, we would like to concentrate on the sea-keeping performances only. Different seakeeping performances of vessels have much to do with principal dimensions and ship forms. So it is quite necessary to discuss the principal dimensions and geometrical characteristics of hull at the very beginning. 1. Elements of Geometrical Characteristics

1.1 'I'hree Cross Sections of Hull Vertical to One Another The middle longitudinal cross section-a longitudinal vertical plane along the centreline of ship length and a symmetrical plane between port and starboard. The midship transversal cross section-a transversal vertical plane at midship. The design water plane-a horizontal plane through design waterline.

1.2. Principal Dimensions The length overall ( LOA )-the max. horizontal distance from bow to stern. The length B P( LBP)--the horizontal distance between the two perpendiculars, i. e. stem and stern. The length W L(LWL)-the length of design waterline or the length of full-load waterline. The breadth moulded ( B )-the max. breadth at design waterline. The depth moulded(D. H)-the vertical height from the upper surface of keel to the surface of upper deck within the midship transversal cross section. Draft(draught) (d)-the vertical height from the upper surface of keel to design waterline. Freeboard(F) -equal to the depth moulded minus draft.

Fig. 1. 1 Principal Dimensions

1.3 Coefficients of Ship Form There are mainly four coefficients for ship form. They are the design water plane

coefficient, the midship transversal cross section coefficient, the displacement coefficient ( referred to as block coefficient as well)and the longitudinal prismatic coefficient. Coefficients of ship form will help you have a better understanding of the hull shape under water and the hull variation along ship length, and directly affect seakeeping performances of vessels. Needless to say, a choice of appropriate coefficients has to be made in the light of the purpose, performance, speed and the like of different ships. 2. Deadweight and Displacement

2.1 Displacement Displacement falls roughly into light-ship displacement( lightload displacement ) and full-load displacement. The light-ship displacement refers to the displacement under which a vessel is loaded on board the ship with crew, crew's personal belongings, spare parts, spare gears and provisions in the absence of cargo, fuel and other consumables; whereas the full-load displacement indicates the displacement under which the load onboard of cargo, complement, fuel and so on has reached to the fullest extent. Besides, for warships, another two concepts, normal displacement and standard displacement, are also adopted for the weight calculation.

2.2 Deadweight It so happens that an owner will bargain with a yard to ask for as largest deadweight as possible because, in a sense, deadweight is a matter of money. For, you see, deadweight is the max. weight of cargo and personnel a ship can carry under the condition of full-load displacement. Or, in other words, deadweight equals to full-load displacement minus the sum of light-load displacement and the weight of consumables onboard, such as water, oil, etc.

In respect to the vessel volume, it is put as the gross tonnage (gt) or the net tonnage(nt). The gross tonnage is calculated on the basis of the total volume of all the compartments and spaces that can be enclosed; while the net tonnage is equal to the gross tonnage minus the volume of the compartments and spaces that are not for cargoes or passengers.Both,gross and net tonnage , are calculated by two simple formulae as indicated by Tonnage Convention 1969.

New Words and Expressions

1. principal dimensions-kch thc ch yu 2. technical specification(spec)-h s k thut,spec 3. code n . -lut 4. Main Group 1-Nhm Chnh 1 5. index n .-danh mc 6. Ship General-D Liu Tng Qut ca Tu 7. general description-m t chung 8. material n . -vt t 9. stability n. tnh n nh 10. classification n-ng kim,hi phn cp 11. drawing n .-bn v 12. supervision n .-s gim st 13.test and trials-thc nghim v th tu 14.delivery-giao tu 15. seakeeping performances-c tnh hng hi 16. geometrical characteristics-c tnh hnh hc 17. hull n thn tu 18. element n .yu t,phn t 19. cross section mt ct ngang 20. vertical a . thng gc 21. longitudinal hng dc 22. plane n mt phng

23. centreline n .ng dc tm 24. symmetrical i xng 25. port n. mn tri 26. starboard n mn phi 27. midship n . a . adv .gia tu 28. transversal a . ngang 29. horizontal a. nm ngang 30. waterline ng nc 31. the middle longitudinal cross section mt ct dc gia tu 32. the midship transversal cross section mt ct ngang gia tu 33. the design water plane ng nc thit k 34. the length overall chiu di ton b 35. max. (maximum) a . ti a 36. bow n mi tu 37.stern n ui tu 38. the length B P chiu di gia hai tr 39. perpendicular n .ng thng gc 40. stem n . sng mi 41. the length W L chiu di ng nc 42 . full-load a . ti y 43. keel n . sng chnh 44. upper deck boong trn 45. draft(draught) n .mn nc 46. freeboard n .mn kh 47. coefficients of ship form h s hnh dng 48. the design water plane coefficient h s ng nc thit k 49. the midship transversal cross section coefficient h s mt ct ngang sn gia 50. the displacement coefficient h s chim nc 51. the block coefficient h s bo 52. the longitudinal prismatic coefficient h s lng tr 53. performance n . ctnh ,thnh tch,hiu nng 54. light-ship displacement (light-load displacement) lng chim nc tu khng 55. full-load displacement lng chim nc ti y 56. crew n. thuyn vin 57. spare parts(spares) ph tng d tr 58. spare gears trang b d phng 59. provision lng thc 60. cargo n .hng ho 61. fuel n. nhin liu 62. consumables n.nhng th c th tiu dng 63. complement n. nh bin 64. normal displacement lng chim nc thng thng 65. standard displacement lng chim nc tiu chun 66. weight calculation php tnh trng lng 67. owner n.ch tu

68. personnel hnh khch 69. sum n. tng s 70. the gross tonnage dung ti tng 71. the net tonnage dung ti tinh 72. compartment n khoang 73. space n. khng gian 74. enclose v bao bc 75.formula n s nhiu formulas hoc formulae cng thc

Verb Phrases and Collocations

l.turn up-pht hin,nhn thy (to discover something ,especially information,after a lot of searching) 2. be regarded as-c coi nh 3. normally speaking -ni chung 4. in spite of -mc d 5. would like to-mong mun 6 concentrate on-tp trung vo 7. have much to do with-c nhiu quan h vi.... 8. have a better understanding of-c c s hiu bit r rng 9. needless to say chng cn phi ni 10. make a choice la chn 11. in the light of prep bi v (because of) 12. and the like (and such like ,and similiar things) v cc th khc na 13. fall into- c hiu,nhn ra (t nhm t fall into place ,nh trong v d :Once I discovered that the woman he had been dancing with was his daughter,everything fell into place-mt khi ti pht hin ra rng ngi ph n thng khiu v vi anh ta chnh l con gi ca anh ,thi mi vic c sng t ,tc l trc y hiu nhm) 14. on board the ship-trn tu 15. be loaded with-c cht ti bi 16. in the absence of-thiu,vng 17. to the fullest extent-t ti mc y nht 18. ask for-i hi 19. under the condition of-trong iu kin 20. in other words-ni cch khc 21. in respect toprep. xt ti 22. be put as-c coi nh 23. on the basis of-trn c s

BI 1-KCH THC CH YU

Nu bn m mt danh mc k thut ,mt ti liu c coi l lut ca ngnh ng

tu,th bn lun thy rng Nhm Chnh 1 trong mc lc l D Liu Tng Qut ca Tu.Ni chung,mc d c th c i cht khc bit nho nh trong cc h s k thut c bit,D Liu Tng Qut ca Tu bao gm m t chung,vt liu,kch thc v dung ti,tnh n nh,ng kim,bn v,vic gim st,th nghim v chy th,giao hng...Tuy nhin ,trong mc nh ny,chng ta ch mun tp trung vo tnh hng hi ca tu.Tnh

hng hi khc nhau ca tu c nhiu mi quan h vi kch thc ch yu v hnh dng ca tu.Bi vy,ngay t u ,chng ta cn tho lun v kch thc ch yu v c tnh hnh hc ca thn tu 1.Cc yu t c tnh hnh hc

1.1.Ba mt ct thn tu thng gc vi nhau Mt ct dc gia t -mt mt phng ng dc theo ng tm ca chiu di tu v mt mt i xng gia mn tri v phi ca tu mt ct ngang gia tu-mt thng ng ngang ti sn gia mt ng nc thit k-mt nm ngang qua ng nc thit k

1.2.Kch thc ch yu Chiu di ton b -khong cch nm ngang ti a gia mi v ui Chiu di gia hai tr-khong cch nm ngang gia hai ng thng gc ,tc l sng mi v sng ui . Chiu di WL-chiu di ca ng nc thit k hoc chiu di ca ng nc ti y. Chiu rng thit k B-chiu rng ti a ti ng nc thit k. Chiu cao mn thit k-chiu cao thng ng t mt trn ca sng chnh ti b mt ca boong trn ti mt ct ngang sn gia tu. Mn nc d-khong cch theo chiu thng ng t mt trn sng chnh ti ng nc thit k. Mn kh F-bng chiu cao mn tr i mn nc. Hnh 1.1 Cc kch thc ch yu

1.3 H s hnh dng tu.Ch yu c bn h s hnh dng tu. l h s ng nc thit k,h s mt ct ngang sn gia,h s lng chim nc (cng gi l h s bo) v h s lng tr dc.H s hnh dng tu gip ta hiu r hn hnh dng thn tu di nc v s bin thin ca thn tu dc theo chiu di v nh hng trc tip ti c tnh hng hi ca tu.Chng cn phi ni ,cn c vo mc ch,c tnh,tc v nhiu th khc ca cc loi tu khc nhau m ta phi chn la cc h s thch hp. 2 Trng ti v Lng chim nc.

2.1 Lng chim nc.Lng chim nc s b c th phn chia thnh lng chim nc tu khng(lng chim nc nh ti) v lng chim nc y ti.Lng chim nc khng ti l lng chim nc m trn tu c thuyn vin, c c nhn ca thuyn vin,ph tng d tr ,trang b v lng thc d tr ,nhng khng c hng ho,nhin liu v cc th tiu dng khc,trong khi lng chim nc y ti l lng chim nc m trn tu c hng ho,nh bin,nhin liu vn vn v t ti mc y nht.Ngoi ra vi tu chin ,ngi ta p dng tnh ton trng lng ca tu hai khi nim khc na l lng chim nc thng thng v lng chim nc tiu chun.

2.2 Trng ti.Thng thng ch tu tho lun mc c vi nh my ng tu t ti trng ti ln nht c th c ,bi v,theo mt ngha no ,trng ti l mt vn tin bc.Bi v,nh ta thy,trng ti l trng lng ti a ca hng ho v hnh khch m con tu c th chuyn ch trong iu kin lng chim nc y ti.Hay,ni mt cch khc,trng ti l lng chim nc y ti tr i tng ca lng chim nc khng ti cng vi trng lng nhng th tiu th trn tu nh nc,du...

Xt v th tch ca tu,ngi ta phn thnh dung ti tng cng v dung ti net,dung ti hu ch. Dung ti tng c tnh da trn tng th tch ca tt c cc phng v khng gian kn trn tu cn dung ti net bng dung ti tng tr i th tch ca nhng phng v khng gian khng cha hng ho v hnh khch.C hai dung ti tng v net c tnh bng hai cng thc n gin nh ch dn trong Cng c Dung Ti 1969 .

Lesson 2 Other Seakeeping Performances (1) Apart from principal dimensions, seakeeping performances cover floatability, roll

and pitch, fast speed, floodability and maneuverability. Floatability One of the important seakeeping performances is the floatability that indicates the

ability of vessel floating positively on water under the condition of a certain amount of deadweight.

When we deal with floatability, we must first be clear about the following two technical terms, i. e. reserve buoyancy and loadline mark.

Fig. 2.1. buoyancy and hydrostatic pressure

Then, what is the reserve buoyancy? As it is known to all, a ship has to obtain a

certain amount of freeboard when she's sailing at sea. That is to say, to give you a concrete idea, any vessel is to retain some volume above water for the sake of extra buoyancy so that its draft is allowed to increase without a sinking tragedy under particular but rare conditions, such as rough sea or serious flooding due to hull damage. For instance, the film, Titanic, popular in every corner of the world and presenting a moving love story to the sentimental audience, describes the fatal hull damage owing to a huge iceberg. This extra buoyancy is called reserve buoyancy; or, to be exact, the reserve buoyancy which is measured by freeboard refers to the watertight volume of hull above load line.

Fig. 2. 2

In respect of load-line mark, it denotes a variety of the max. drafts of vessels in different seasons and at varied navigating zones.

Stability One more seakeeping performance is the stability which is the ability that vessels

will incline when affected by an exterior force, such as wind, wave, etc. , and will restore its original position on the force removal. Stability is, of course, of great importance to shipbuilding since its failure will always lead to heavy loss of life. History has sadly witnessed tragic sinking of vessels so many a time by reason of poor stability.

Vessel inclination may be divided into trim and heel. As the metacenter of transversal inclination is much more essential than that of longitudinal inclination, the emphasis is invariably laid on the transversal stability and discussions are often limited to the small metacentric angle under 15 degrees.

In order to obtain fine stability, precautions will normally be taken in two different ways.

Fig. 2.3

On one hand, gravity center is to be lowered; on the other hand, metacenter to be raised. The gravity center of a ship to be calculated by means of an inclination test. The test is generally to be performed in calm water and with lovely weather. If you have got a drydock for the test, so much the better.

Fast Speed Another seakeeping performance is the fast speed or rapidity which describes the

ability for a ship to gain faster speed at lower consumption of power. Vessels will be affected mainly by water resistance during voyage. We do not bother

our brain about air resistance because it is far smaller than water resistance. Perhaps, the only exception is high-speed boats.

Water resistance to be encountered by a ship consists of friction resistance, swirl resistance and wave-forming ( wave-making ) resistance.

There are two ways to raise ship speed, namely, to minimize water resistance and to increase main engine power. To achieve this, a bulbous bow is widely used in many types

of ships and the rated horsepower of main engines is generally to be over two times as big as the effective horsepower of ships.

Fig. 2. 4 Wave-forming resistance

New Words and Expressions

1.floatability n tnh ni 2. roll n lc ngang 3. pitch n lc dc 4. fast speed (rapidity) tnh tc 5. floodability n.tnh chng chm 6. maneuverability n.tnh iu khin 7. floating positively ni dng,ni hon ton 8. technical term thut ng k thut 9. reserve buoyancy sc ni d tr 10. load line mark du ti y 11. rough sea bin ng 12. flood v.chm,ngp nc 13. watertight a.kn nc 14. navigating zone vng hng hi

15. incline v.nghing 16. exterior force ngoi lc 17. inclination n s nghing 18. trim n nghing dc. 19.heel n nghing ngang 20. the metacentre of transversal inclination tm nghing ngang 21. the metacentre of longitudinal inclination tm nghing dc 22. transversal stability n nh ngang 23. small metacentric angle gc nghing nh 24. gravity centre trng tm

25. metacentre n tm nghing 26. inclination test th nghing 27. consumption n . s tiu th 28. resistance n.sc cn 29. voyage n . hnh trnh

30. high-speed boat xung cao tc 31. friction resistance sc cn ma st 32. swirl resistance sc cn xoy 33. wave-forming (wave-making) resistance sc cn do to sng 34. minimize ti thiu 35. bulbous bow mi qu l 36. the rated horsepower m lc danh nh 37. main engine (ME) my chnh 38. the effective horsepower m lc hu hiu

Verb Phrases and Collocations

1. under the condition of trong iu kin 2.a certain amount of mt lng nht nh 3. deal with sth bn v ci g, cp vn g 4. be clear about lm sng t 5. to give you a concrete idea cho ta mt ngha c th 6. for the sake of v (for the sake of peace v ho bnh) 7. in every corner of the world khp mi ni trn th gii 8. present sth to sb trnh by ci g cho ai 9. to be exact (exactly speaking) ni mt cch chnh xc 10. in respect of xt v phng din 11.work out tho ra 12 . lead to dn ti 13. so many a time rt nhiu ln ,tng t vi so many times 14. be divided into c chia thnh 15. be laid on da trn 16. be limited to c gii hn 17. in order to 18. take precautions ch phng 19. on one hand. , on the other (hand) v mt ny... v mt kia 20. by means of thng qua 21. so much the better nh th cng tt 22. bother one's brain about bn tm v 23. consist of bao gm 24. be widely used in c dng rng ri

BI 2 CC C TNH HNG HI KHC

Ngoi kch thc ch yu,c tnh hng hi bao gm tnh ni,lc ngang v dc.tnh tc ,tnh chng chm v tnh iu khin

Tnh ni

Mt trong nhng c tnh hng hi quan trng l tnh ni ,mt tnh cht nu r kh nng tu ni c trn mt nc trong iu kin trng ti no . Khi chng ta cp ti tnh ni rc ht chng ta phi lm r hai thut ng k thut , l sc ni d tr v du hiu ng nc c ti

Hnh 2.1 Sc ni v p lc thy tnh Vy,th no l sc ni d tr ?Nh tt c chng ta u bit,contu khi i bin c

mt lng mn kh no . gip cho bn mt tng c th, l mun ni ti vic bt k mt con tu no cng gi li mt s th tch nm trn mt nc lm sc ni d tha ; l mn nc ca tu cho php tng ln m khng dn ti bi kch chm tu trong nhng iu kin c th nhng khng phi him hoi nh bin ng hay thn v tu b h hi.V d phim Titanic,mt cun phim ni ting ton cu trnh din mt chuyn tnh cm ng cho gii cng chng mn cm ,trong phim m t vic thn tu b h hi khng khep do mt ni bng khng l.Sc ni d gi l sc ni d tr,hay ni chnh xc hn,sc ni d tr o bng mn kh ,l th tch kn nc ca thn v nm trn ng nc c ti.

V ng nc c ti, l mt lot cc ng nc ti a ca tu trong cc ma khc nhau v thay i ty theo vng hng hi.

Tnh n nh Mt c tnh hng hi na l tnh n nh l kh nng con tu b nghing khi c

ngoi lc nh go,sng ...tc dng v s khi phc li v tr ban u khi lc c gi b.Tt nhin tnh n nh c tm quan trng to ln vi ngnh ng tu v khim khuyt ca n lun lun dn ti nhng tn tht to ln v sinh mng. Lch s au bun chng kin nhng bi kch chm tu trong nhiu ln v l do km n nh.S nghing ca tu c th phn thnh nghing dc v nghing ngang.V tm nghing ngang lun thit yu hn tm nghing dc nn ta lun phi nhn mnh ti n nh ngang v thng gii hn tho lun ti gc nghing nh di 15 . c c n nh tt,lun ch ti hai im:Mt mt phi h thp trng tm,mt khc phi tng chiu cao tm nghing.Trng tm ca tu c tnh ton thng qua vic thnghing lch.Vic th ni chung c tin hnh trong nc yn tnh vi thi tit tt p.Nu th trong kh th cng tt.

Tnh tc cao Mt c tnh hng hi khc l tnh tc tc l kh nng ca con tu t c tc

cao nht vi lng tiu th cng sut t nht. Trong hnh trnh ,con tu ch yu chu tc ng sc cn ca nc.Chng ta khng bn tm ti sc cn khng kh v n qu nh so vi sc cn ca nc.C l ,ch ngoi tr xung cao tc.

Sc cn ca nc m con tu gp phi bao gm sc cn ma st, sc cn xoy v sc cn do to sng.C hai cch tng tc ca tu, l,gim thiu sc cn ca nc v tng cng sut my chnh. thc hin vic ,mi qu l thng c p dng rng ri cho nhiu loi tu v cng sut danh nh ca my chnh thng hai ln ln hn cng sut hu hiu ca tu .

Hnh 2.4-Sc cn do to sng

Lesson 3-Other Seakeeping Performances(2)

Roll and Pitch

When floating on water or sailing at sea, vessels will roll or pitch owing to wave motions as well as the influence of wind, current and propeller. The fatal results of excessive roll and pitch are as follows: 1. First, the ship upsetting arising from excessive inclination due to roll. 2. In the next place, the hull structure damage because of sharp roll and pitch as well as the violent movement of bulk cargoes, or even worse the hull might break. 3. Still next, the affection on the propulsion plant, i. e. the increase of water resistance and the reduction of speed by reason of roll and pitch. 4. Then, the affection on proper operation of various kinds of machines and instruments. 5. Last of all, the hard working condition which causes the crew to be seasick.

Therefore, we have to take roll and pitch into our consideration during the design stage, for they are closely related to the whole seakeeping performance.

As you know, the roll period is greatly concerned with the initial metacentric height and, in some degree, stability is contrary to roll. It seems to be strange that violent roll, as many people might think, is not derived from poor stability.

So far different stabilizing units have been invented, and found wide application to decreasing roll and pitch. Common stabilizing units now in practical use are bilge keels, stabilizers and wing,buoyant tanks.

Fig. 3.1 stabilizer

Floodability

Floodability states the ability for a vessel to keep afloat with sufficient floatability, stability and other seakeeping performances in case one or several compartments are

flooded. Should sea damage take place, reserve buoyance would be the principal condition to keep a vessel afloat. With the help of the watertight bulkheads and decks which separate the inside of hull into a number of compartments and spaces, reserve buoyance enough is to be retained so that the intake of sea water may be confined to the damaged compartment without water pouring into the adjacent compartments.

Maneuverability

The last seakeeping performance that we are coming to is maneuverability, which refers to the ability for a vessel to retain or change its course in accordance with the pilot's intention.

Maneuverability is composed of two abilities, that is, the directional stability and the turning ability. The former indicates the ability for a vessel to keep to its given course, while the latter sets forth the ability for a vessel to change its course. Ocean-going vessels require strict directional stability, whereas short-range ships ask for a better turning ability. Moreover, the smaller the turning circle of vessels, the better their turning ability.

In the guarantee of vessel maneuverability, a steering gear of fine quality is to be provided, rudder being its primary component.

New Words and Expressions

1. current n. dng chy 2. propeller n chn vt 3 . upset v. lt nga 4. excessive a .qu mc 5. bulk cargo hng ri,hng x 6. the propulsion plant trang b y tu 7. operation vic iu hnh,vic s dng 8. instrument n.dng c 9. seasick a.say sng 10. design stage giai on thit k 11. the roll period chu k lc ngang 12. initial metacentric height chiu cao tm nghing ban u 13. stabilizing unit thit b chng lc 14. bilge keel sng hng,vy bn hng 15. stabilizer n thit b chng lc 16. wing buoyant tank kt ni hai bn cnh g 17.floodability tnh chng chm 18.reserve buoyance sc ni d tr 19. state v. pht biu,ni r,tuyn b 20. sufficient 21. sea damage s h hi trn bin 22. bulkhead n .vch 23. deck n .boong 24. intake n. a vo,np vo 25. sea water (SW) nc bin

26.retain v.ngn,gi li,tip tc c 27. pour v. vo,rt vo 28.confine v.giam gi,gi li 29 . adjacent a.k cn,k bn 30.maneuverability n.tnh iu khin,tnh quay tr 31.refer to v.ni ti,k ti

32 . course n .hnh t r nh 33. pilot n .hoa t iu 34. intention n. nh 35. directional stability n nh hng 36. turning ability kh nng quay tr 37. short-range a .tm ngn 38. turning circle ng trn quay tr 39. guarantee n. v. m bo,cam kt 40. steering gear thit b li 41. rudder n.bnh l i 42. component n. thnh phn

Verb Phrases and Collocations

1. as follows nh sau 2. arise from sinh ra t 3.in the next place tip theo 4. last of all cui cng 5. take sth. into ones consideration xt ti 6. be related to c lin quan ti 7. be concerned with cp ti 8. in some degree trong mc no 9. be contrary to tri ngc vi 10. derive from sinh ra t ; be derived from c sinh ra t 11. so far trong chng mc,ti chng mc 12. find wide application to c p dng rng ri 13. in use c s dng 14 . in case conj. trong trng hp 15. with the help of vi s h tr ca 16. separate A into phn chia A thnh 17. a number of mt cht 18. be confined to c gi li 19. come to i ti 20. in accordance with cn c vo 21. be composed of c hp thnh bi 22. the former.the latter.ci trc.ci sau 23. keep to gi li 24. set forth cng b ,nu ra, a ra 25. in the guarantee of c bo m