Basic Deck Measurments

Question 1

Longitudinal Measurments

Answer 1

Measurements from stern to bow (e.g. keel)

Question 2

Transverse measurements

Answer 2

Measurements from port to starboard (e.g. beam)

Question 3

Vertical Measurments

Answer 3

Measurements from top to bottom (e.g. draft)

Question 4

LOA

Answer 4

Length Overall, includes all extremes, important for docking, parallel to baseline

Question 5

Keel

Answer 5

The spine of the ship

Question 6

Shear

Answer 6

Curvature if deck from stern to bow. Forward > aft, increases buoyancy in bad weather

Question 7

Beam (or breadth)

Answer 7

The width of the ship, wider = more stable

Question 8

Extreme beam

Answer 8

Beam plus any projections

Question 9

Tumble home

Answer 9

Inward slope of ship’s hull.

Question 10

Flare

Answer 10

Opposite of tumble home, outward slip of ship’s side. Drier deck with more surface area. Less “shipping of seas”

Question 11

Air draft

Answer 11

Vertical distance from water line to highest point

Question 12

Apparent draft

Answer 12

Indicated on side, forward, aft, and midship.

Question 13

True draft

Answer 13

Calculated from forward and aft perpendiculars (FP & AP)

Question 14

Freeboard

Answer 14

Distance between deck and waterline

Question 15

Camber

Answer 15

Curve of the deck, moves water out to the side.

Question 16

Depth

Answer 16

Lowest point of the hull for the side of the deck

Question 17

Dead rise

Answer 17

Slant of keel to bilge. Also called rise of bottom or ride of floor.

Question 18

Moulded dimensions

Answer 18

Measured from the inside of shell. Equal to minus 2x the thickness of shell plating.