12.(1) Every power-driven vessel navigating on any canal shall be furnished with an efficient whistle.
12.(2) When vessels are in sight of one another the master of a power-driven vessel under way in taking any of the courses hereinafter referred to in this Bye-law shall indicate that course by (the) following signals on such whistle, namely: One short blast to mean "I am altering my course to starboard", two short blasts to mean "I am altering my course to port", three short blasts to mean "my engines are going astern", four short blasts to mean "I am about to turn or to turn round". This signal shall be followed after a short interval by one short blast if turning to starboard or two short blasts turning to port and shall be repeated to any approaching vessel, whereupon such approaching vessel shall take action to avoid collision.