ColRegs – avoiding collisions at sea
ColRegs Rule 8: Action to avoid collision
(a) Any action taken to avoid collision shall be taken in accordance with the Rules of this Part and shall, if the circumstances of the case admit, be positive, made in ample time and with due regard to the observance of good seamanship. (b) Any alteration of course and/or speed to avoid collision shall, if the circumstances of the case admit, be large enough to be readily apparent to another vessel observing visually or by radar; a succession of small alterations of course and/or speed should be avoided….
(From Nautical Rules of the Road – ColRegs for power boating and sailing – a Safe-Skipper App)