List ◦ The effect of a list is to hinder a turn in the direction of the list and assist a turn away from it. A list to port decreases the tactical diameter of a ship turning to starboard, and vice versa.
Speed ◦ The effect of speed on tactical diameter will vary from one type of ship to another. Often higher speed may lead to a greater tactical diameter because the rudder may stall. Modern rudders, on smaller ships, however, are able to operate satisfactorily at higher water speeds and greater angles, and hence the tactical diameter may not vary much with speed. Indeed, on some ships there is a best speed giving the minimum tactical diameter and at higher or lower speeds the tactical diameter is greater. Watchkeeping officers should be fully aware of the,effect of speed on the turning qualities of their ship.