Q.What is Tactical diameter of the ship ? Is it constant or it differs by any external factors ?

Q1: "What is Tactical Diameter of the ship?"

A1: SETTING: While a vessel is underway, with way apon it, steering is applied at "full rudder" (either right or left). The rudder will have a delayed "bite into the water", which manifests as "advance" (distance remaining along original course) and "transfer" (distance diverging the original course, into the direction of the turn) before the rudder has stablized the turn. DEFINITION: As the ship proceeds through a turn, the distance measured from the point initiating the turn to the point at which the vessel achieves a course 180-degrees opposite the original couse.

Q2: "Is it constant, or does it differs by any external factors?"

A2: The Tactical Diameter is usually thought of as initiating at full-speed and with full-rudder. It is subject to a number of factors:

Factors which affect the diameter can include: the density of the water, any wind present, the depth of water, the speed of the vessel relative to any water current, the length of the vessel, and the size and location of the rudder(s) ... (among some others).