Lateral Resistance As a ship commences to turn and thereafter for the duration of a turn, the ship is sliding sideways through the water. This results in a large build up of water resistance which continually opposes the rudder force and we can refer to
Vessel Head to Wind with Headway Vessel making Headway through the water, and Heading directly into the Wind. W is now well forward of amidships, and in fact very close to P; the wind is exerting no turning moment, or sideways force, on the vessel.
Ahead Movement of the Propeller The effect of transverse thrust whilst making an ahead movement is arguably less worrying than that of an astern movement, perhaps because the result is less noticeable. (a) The helical discharge from the propeller creates a larger pressure on the
Stopped In this situation no forces are involved and the ship has its centre of gravity approximately amidships when the ship is stopped. Making Headway Two forces now come into play, firstly the forward momentum of the ship and secondly, longitudinal resistance to forward momentum,