Vessel Stability

Question 1

Righting lever?

Answer 1

GZ
Perpendicular distance between the lines of force of gravity downward due to weight and buoyancy acting up on a vessel when she is heeled

Question 2

Righting moment?

Answer 2

W x gz

Moment tending to bring the vessel upright when she is heeled

Question 3

Centre of buoyancy?

Answer 3

Geometric Centre of the underwater volume of the ship.

The point where total upthrust of the displaced water acts

Question 4

Metacentre?

Answer 4

Intersection of vertical lines through the centre of buoyancy as the ship heels

Question 5

Displacement?

Answer 5

Weight of a vessel

Question 6

Dock water allowance?

Answer 6

Amount a ship may submerge her load line marks when in density of water between fresh and salt so she will be on her marks when in salt water

Question 7

TPC?

Answer 7

Tonnes per cm

Weight to load or discharge to change the mean draught by 1cm

Question 8

Relative density?

Answer 8

Density of substance / density of fresh water

Question 9

Mass?

Answer 9

Quantity of matter in a body

Question 10

Weight?

Answer 10

W =mg

Question 11

Buoyancy?

Answer 11

Vertical force upwards due to weight of liquid displaced by the floating ship

Question 12

Freeboard?

Answer 12

Vertical distance from water line to decline at midships

Question 13

Draft?

Answer 13

Vertical distance from waterline to the lowest part of the vessel

Question 14

Fwa?

Answer 14

Amount a ship may submerge her load lines in fresh water so she will float at her summer load marks in salt water