Section 15 in The Port Rules for the Port of Bombay
15.
Every ocean going vessel or tug towing an ocean-going when passing through the Docks Channels shall sound the steam whistle at short intervals as a warning to other vessles to get out of the way, and a vessel at anchor in the stream shall do likewise when getting under way, and it shall be duty of all such other vessels to see that a free passage is preserved through the Docks Channels for every such ocean-going vessel or tug towing an ocean going vessel.
