Glossary and Definitions

Question 1

Length Overall (LOA)

Answer 1

The Length between the extreme forward and aft points

Question 2

Length on the Waterline (LWL)

Answer 2

Length along the designed waterline from the furthest aft and forward points

Question 3

Length Between Perpendiculars (LBP)

Answer 3

Distance on the summer load waterline from the fore side of the stem to the after side of the rudder post.

Question 4

Breath Moulded (Bmld)

Answer 4

Maximum Breadth measured at midships to the outside of the frameline (inside of plating).

Question 5

Depth Moulded (Dmld)

Answer 5

Vertical distance at amidships from the keel to the uppermost deck, taken from within the inside of the plating.

Question 6

Draught Moulded (Tmld)

Answer 6

Vertical distance from the water surface to the inside of the plating at the keel.

Question 7

‘Even-Keel’

Answer 7

Waterline is parallel to the keel

Question 8

‘Trimmed by stern’

Answer 8

The draught is greatest at the stern.

Question 9

‘Trimmed by head’

Answer 9

The draught at the bow is greatest.

Question 10

Freeboard

Answer 10

Vertical distance from the summer load waterline to the top of the freeboard deck plating measured at amidships.
(Load Line regulations prescribe minimum freeboard)

Question 11

Extreme dimensions

Answer 11

Measurements taken to the outside of the plating (rather than moulded)

Question 12

Sheer

Answer 12

Longitudinal curvature of the deck between the ends of the ship.

Question 13

Sheer Strake

Answer 13

Strake of upper-most continuous shell plating at deck level.

Question 14

Shell

Answer 14

Outer-plating

Question 15

Superstructure

Answer 15

Decked structure above the upper deck, the outboard sides of which are formed by shell plating.

Question 16

Deckhouse

Answer 16

Superstructure found on the upper deck of a ship which doesn’t extend across the full breadth of the ship.

Question 17

Forecastle Deck

Answer 17

Superstructure at the bow formed by having a raised deck.

Question 18

Poop Deck

Answer 18

Superstructure at the stern formed by having a raise deck. (The deckhouse normally found on top)

Question 19

Hatch cover

Answer 19

Cover creating a waterproof closure

Question 20

Combing

Answer 20

Vertical plating around a hatchway. The height of combing reflects the position and relative exposure of the hatch.

Question 21

Bulkhead

Answer 21

Vertical transverse or longitudinal division of a ship forming a compartment.

Question 22

Double-bottom

Answer 22

Longitudinal structure created by a ‘tank-top’ which runs parallel to the bottom shell over the length of the ship. (void along bottom)

Question 23

6 degrees of freedom

Answer 23

1) heave (vertical), 2) yaw (rotation around heave)
3) surge (forwards/ backwards)) 4) roll (rotation around surge)
5) sway (side to side) 6) pitch (rotation around sway)

Question 24

Lines Plan

Answer 24

Drawing consisting of the profile, half breadths and body-plan of a ship, illustrating it’s form.

Question 25

Displacement Stations

Answer 25

Equally spaced divisions along the length between perpendiculars. (O= aft perpendicular)

Question 26

Hydrostatic Particulars

Answer 26

Properties of the hull form derived from the lines plan. Typically areas, volumes, coefficients of form and centroids. Allow for evaluation of a ships performance and dictate the classification of a ship.

Question 27

Bonjean Curves

Answer 27

Curves of transverse sectional areas of the ship, drawn along a vertical scale of draught.

Question 28

Archimedes' Principle

Answer 28

Upthrust on a body = Weight of fluid displaced

Question 29

Density of Fresh water

Answer 29

1 tonne/m^3

Question 30

Density of Sea water

Answer 30

1.025 tonnes/m^3

Question 31

3 Zones of a Ship

Answer 31

Entrance, Parallel Mid-Body and Run

Question 32

Entrance

Answer 32

Length of the ship forward of the parallel mid-body

Question 33

Parallel mid-body

Answer 33

Length of the ship for which the cross section is constant.

Question 34

Run

Answer 34

Length of the ship aft of the Parallel mid-body

Question 35

Lightship

Answer 35

Combined mass of unladen ship comprised of three components: 1) Steelmass 2) Mass of main and auxiliary machinery 3) Wood and outfit mass

Question 36

Deadweight

Answer 36

Mass of payload and consumables

Question 37

Tonnes per Centimeter Immersion (TPC)

Answer 37

How many tonnes of additional cargo are required to sink the ship 1cm lower into the water. (increase the draught by 1cm)

Question 38

Tonnage

Answer 38

Indicator of size based on volume.

Question 39

Gross Tonnage

Answer 39

Indicator of overall size

Question 40

Net Tonnage

Answer 40

Indicator of carrying capacity