Tactical diameter
# Tactical diameter

The tactical diameter of a ship is the distance:

* travelled on sea surface
* during a turning circle test
* with maximum rudder angle
* by the center of gravity of a ship
* taken perpendicular to the initial track followed at approach speed
* when the heading has changed by 180°

The ratio of the tactical diameter divided by the ship's length between perpendiculars gives a dimensionless parameter which can be used to compare ships maneuverability.

