1. In reduced visibility, vessels and floating equipment stationary in or near the fairway outside harbours or places specially designated by the competent authorities for berthing, shall be on listening watch on the ship-ship channel. As soon as they hear by radiotelephone, of the approach of other vessels, or as soon and as long as they hear from an approaching vessel one of the signals prescribed in article 6.32, paragraph 4 or article 6.33, paragraph 1 (b), they shall indicate their position by radiotelephone or give sound signals as follows:
(a) When they are to the left of the fairway (for an observer facing downstream):
One peal of a bell;
(b) When they are to the right of the fairway (for an observer facing downstream):
Two peals of a bell;
(c) When their position is uncertain:
Three peals of a bell.
These signals shall be repeated at intervals of not more than one minute.
2. The provisions of paragraph 1 above shall not apply to vessels in a pushed convoy other than the pusher. In the case of a side-by-side formation, they shall apply only to one vessel in the formation. In the case of a towed convoy, they shall apply only to the towing vessel and the last vessel in the convoy.
3. This article shall also apply to vessels grounded in or near the fairway which may present a danger to other vessels.