next to the engine order telegraph dial on the user interface there is a little round button.
click the button and the telegraph dial turns into a knot meter indicating the current speed.
if you click somewhere between 1 and 2 knots, the speed of the engines will reduce to lower RPM. you can see your engine tachometers on the tach gauges directly over the planesmen in the command room view.
the needle should point to about 50 RPM
of course the trade off is that you are barely outrunning most garden snails... let alone hedge hogs and depth charges.
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