NEECVideos Naval Arch Playlist Flashcards
Bow
Front of ship
Stern
Back of ship
Port
Left of the ship
Starboard
Right off the ship
Standing in the middle, walking towards the bow, you are going _________
Forward
Standing in the middle, walking towards the stern, you are going ________
Aft
Centerline plane
Symbol looks like an entangled CL, cuts the ship like a banana split
Midship plane
Cuts the ship perpendicular to motion. Two opposing C’s whose curves form an X, then boxed in.
Waterline plane
The plane where the waterline bisects the ship.
Waterlines
A bunch of waterlines run from the keel line to the top deck
Buttocks
Centerlines of the ship, long slices of hull. The closer the lines, the more curvature.
Stations
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)
Lines drawing basics
Profile view shows buttock lines,
Plan view shows waterlines
Body plan shows stations
LOA:
Length Overall; Important for docking the ship (how much space do i need?)
LWL:
Length of Waterline; more important for predicting performance.
LBP
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,
Beam:
Width of the ship, almost always at midship.
Depth
Overall height of the hull
Draft
Height of the hull that is beneath the waterline.
Freeboard
Length of hull above the waterline
Commonly used ratios
L/B Length to beam
L/D Length to depth
B/T Beam to draft
B/D Beam to depth
Waterline area
Slice off the hull at the waterline. A<subscript>w</subscript>
Waterplane coefficient
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>
Center of Flotation (CF)
The ship tips along this point while loading. There are 3 different coordinates for this point. Longitudinal, transverse, and vertical
LCF
Longitudinal Center of Floatation; almost always measured from midships but it can also be defined by the aft perpendicular or fore perpendicular.
Longitudinal moment of inertia
Moment of the area above the trim axis??? (Calculated by a hydrostatics program)
Transverse moment of inertia
Second moment of inertia, the space above the centerline
Volume of displacement
Volume of water displaced by the ship
(Volume shorthand has a line above it, not to be confused with velocity.)
Center of Buoyancy,
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)
Midship Station Area:
A<subscript>m
The area below design waterline of a transverse slice at the midship</subscript>
Sectional area curve
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.
Block coefficient
C<subscript>B
Vol/LBT (L usually = LWL)
Higher block coefficients are fuller, low block coefficients are finer.
.45 (destroyer) .85 (large tanker)</subscript>
Prismatic coefficient
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>
Midship section coefficient
C<subscript>M
Fullness of midship section
A<subscript>M/BT
NOTE: Cb=Cp x Cm</subscript></subscript>
Notes
All hydrostatic properties change with draft
Molded dimensions do not include plate thickness
