LT 3 LT F LT - United States Naval Academy Ch2 HW... · 2-1 A small boat weighing 40 LT has a...
Transcript of LT 3 LT F LT - United States Naval Academy Ch2 HW... · 2-1 A small boat weighing 40 LT has a...
2-1 A small boat weighing 40 LT has a submerged volume of 875 ft3 when traveling at 20 kts in
seawater. (ρ = 1.99 lb·s2ft4 ; 1 LT = 2240 lb)
(a) Calculate the magnitude of the hydrostatic support being experienced by boat.
FBuoyancy = ρgVsub = 1.99 lb·s2ft4 · 32.2 ft
s2 · 875 ft3 = 56,068 lb · 1 LT2,240 lb = 25 LT
(b) What other type of support is the boat experiencing?
In addition to hydrostatic support, this boat is experiencing hydrodynamic support/lift.
(c) Calculate the magnitude of this other type of support.
FHydrodynamic = Wboat − FBuoyancy = 40 LT − 25 LT = 15 LT
(d) What will happen to the submerged volume of the boat if it slows to 5 knots? Explain your
answer.
Hydrodynamic lift is proportional to V 2boat. As the boat slows, the reduction in hydrodynamic
support will cause the boat weight to exceed the total lift so the boat will sink down (draft, T ,
will increase). As T increases, Vsub increases so Fbuoyancy increases until a new equilibrium is
reached at a new, deeper, draft.
12. hi
2-4 Sketch a profile of a ship and show the following:
(a) Forward Perpendicular
(b) After Perpendicular
(c) Sections, assuming the ship has stations numbered 0 through 10.
(d) Length Between Perpendiculars
(e) Length Overall
(f) Design Waterline
(g) Amidships
13. hi
2-5 Sketch a section of a ship and show the following:
(a) Keel
(b) Depth
(c) Draft
(d) Beam
(e) Freeboard
14. hi
+x
+y
+zC
. (translation)_H
eave_
A.(translation)
_Surge_
B. (translation)
_Sway_
E. (rotation)_Trim
_/_Pitch_
D. (rotation)
_Roll_/_List_/_H
eel_
F. (rotation)_Yaw
_
G. V
iewed from
bow_B
ody_ Plan
H. V
iewed from
side_Sheer_ Plan
I. View
ed from top
_Half_ -_B
readth_ Plan
J. _Section_ Line
K. _B
uttock_ Line
L. _Water_ Line
M. H
orizontal ref plane forvertical m
easurements
_Baseline_
N. Forw
ard ref plane forlongitudinal m
easurements
_Forward_ _Perpendicular_
O. A
ft ref plane forlongitudinal m
easurements
_Aft_ _Perpendicular_
P. Middle ref plane for
longitudinal measurem
ents_M
idships_
Q. Longitudinal ref plane for
transverse measurem
ents_C
enterline_
R. D
istance between “N
.” & “O
.”_Lpp_=_Length_ _B
etween_ _Perpendicular_
S. Width of the ship
_Beam
_
EN400 Chapter 2 Prob 6
2-7 For this question, use a full sheet of graph paper for each drawing. Choose a scale that gives the
best representation of the ship’s lines. Use the FFG-7 Table of Offsets given on the following page for
your drawings.
(a) For stations 0-10 draw a Body Plan for the ship up to the main deck. Omit stations 2.5 and 7.5.
(b) Draw a half-breadth plan showing the 4 ft, 12 ft, 24 ft waterlines, and the deck edge.
(c) Draw the sheer profile of the ship.
Prob 8
Prob 9
Prob 9
Prob 10
Prob 11
Prob 12
Prob 13
Prob 14
Prob 15, 1615)
16)
Prob 17, 1817)
18)
Prob 19, 2019)
20)