NEECVideos Naval Arch Playlist

Question 1

Bow

Answer 1

Front of ship

Question 2

Stern

Answer 2

Back of ship

Question 3

Port

Answer 3

Left of the ship

Question 4

Starboard

Answer 4

Right off the ship

Question 5

Standing in the middle, walking towards the bow, you are going _________

Answer 5

Forward

Question 6

Standing in the middle, walking towards the stern, you are going ________

Answer 6

Aft

Question 7

Centerline plane

Answer 7

Symbol looks like an entangled CL, cuts the ship like a banana split

Question 8

Midship plane

Answer 8

Cuts the ship perpendicular to motion. Two opposing C’s whose curves form an X, then boxed in.

Question 9

Waterline plane

Answer 9

The plane where the waterline bisects the ship.

Question 10

Waterlines

Answer 10

A bunch of waterlines run from the keel line to the top deck

Question 11

Buttocks

Answer 11

Centerlines of the ship, long slices of hull. The closer the lines, the more curvature.

Question 12

Stations

Answer 12

A bunch of midship sections, generally, stations that are forward of the midship are on the right, aft of the midship is on the left (this presumes port and starboard are symmetrical)

Question 13

Lines drawing basics

Answer 13

Profile view shows buttock lines,
Plan view shows waterlines
Body plan shows stations

Question 14

LOA:

Answer 14

Length Overall; Important for docking the ship (how much space do i need?)

Question 15

LWL:

Answer 15

Length of Waterline; more important for predicting performance.

Question 16

LBP

Answer 16

Line Between Perpendiculars; forward perpendicular is often at the intersection of the bow and waterline. Aft perpendicular is where the stern intersects with the waterline, but it could also be where the rudder/propeller shaft/etc. goes,

Question 17

Beam:

Answer 17

Width of the ship, almost always at midship.

Question 18

Depth

Answer 18

Overall height of the hull

Question 19

Draft

Answer 19

Height of the hull that is beneath the waterline.

Question 20

Freeboard

Answer 20

Length of hull above the waterline

Question 21

Commonly used ratios

Answer 21

L/B Length to beam
L/D Length to depth
B/T Beam to draft
B/D Beam to depth

Question 22

Waterline area

Answer 22

Slice off the hull at the waterline. A<subscript>w</subscript>

Question 23

Waterplane coefficient

Answer 23

C<subscript>w=A waterplane/LB
(L usually equals LWL.)
Describes the fullness or fineness of the waterplane.
Sample values: .67 (destroyer); .92(very large tanker)</subscript>

Question 24

Center of Flotation (CF)

Answer 24

The ship tips along this point while loading. There are 3 different coordinates for this point. Longitudinal, transverse, and vertical

Question 25

LCF

Answer 25

Longitudinal Center of Floatation; almost always measured from midships but it can also be defined by the aft perpendicular or fore perpendicular.

Question 26

Longitudinal moment of inertia

Answer 26

Moment of the area above the trim axis??? (Calculated by a hydrostatics program)

Question 27

Transverse moment of inertia

Answer 27

Second moment of inertia, the space above the centerline

Question 28

Volume of displacement

Answer 28

Volume of water displaced by the ship
(Volume shorthand has a line above it, not to be confused with velocity.)

Question 29

Center of Buoyancy,

Answer 29

B the center of the displaced volume
Longitudinal Center of Buoyancy (LCB)
Vertical Center of Buoyancy (KB)
(Transverse center of buoyancy is usually in the middle due to port/starboard symmetry)

Question 30

Midship Station Area:

Answer 30

A<subscript>m
The area below design waterline of a transverse slice at the midship</subscript>

Question 31

Sectional area curve

Answer 31

Graph out a draft at the design water line, some above and some below, to help determine how your ship is going to behave at different heights.

Question 32

Block coefficient

Answer 32

C<subscript>B
Vol/LBT (L usually = LWL)
Higher block coefficients are fuller, low block coefficients are finer.
.45 (destroyer) .85 (large tanker)</subscript>

Question 33

Prismatic coefficient

Answer 33

C<subscript>P
Describes the fineness of the bow and stern without the influence of the midship fullness.
Vol./A<midship>L (L usually =LWL)
E.g .57 (destroyer) .85(large tanker)</midship></subscript>

Question 34

Midship section coefficient

Answer 34

C<subscript>M
Fullness of midship section
A<subscript>M/BT
NOTE: Cb=Cp x Cm</subscript></subscript>

Question 35

Notes

Answer 35

All hydrostatic properties change with draft
Molded dimensions do not include plate thickness