Squat

Question 1

A vessel proceeding on the starboard side of a shallow river may experience “bank effect”. State
how this would affect the vessel.

Answer 1

The forward positive pressure is constrained on one side causing the bow of the vessel to be pushed to port.

The negative pressures aft of the pivot point will suck the stern of the ship towards the bank

Question 2

Squat is not an increase in draught. State what it is

Answer 2

A reduction in under keel clearance.

Question 3

State the cause of squat

Answer 3

Increased speed of water flow under the hull causes a drop in pressure which leads to a loss
in buoyancy causing a fall in W/L immediately adjacent to the water envelope which leads to
the loss of UKC.

Question 4

State the most effective way of reducing squat

Answer 4

Reducing speed as squat varies proportionately to v²

Question 5

State how “bow cushion” effect assists a vessel when navigating in the confines of a canal

Answer 5

It will help to keep the vessel central provided the vessel is restricted on both sides.