Rule 35

Sound Signals in Restricted Visibility.

(a) A power driven vessel making way through the water shall sound at intervals of not more than 2 minutes one prolonged blast.

(b) A power driven vessel underway but stopped and making no way through the water shall sound at intervals of no more than 2 minutes two prolonged blasts in succession with an interval of about 2 seconds between them.

(c) A vessel not under command, a vessel restricted in her ability to manoeuvre, a vessel constrained by her draft, a sailing vessel, a vessel engaged in fishing and a vessel engaged in towing or pushing another vessel shall, instead of the signals prescribed in paragraph (a) or (b) of this Rule, sound at intervals of not more than 2 minutes three blasts in succession, namely one prolonged followed by two short blasts.

(d) A vessel engaged in fishing, when at anchor, and a vessel restricted in her ability to manoeuvre when carrying out her work at anchor, shall instead of the signals prescribed in paragraph (g) of this Rule sound the signal prescribed in paragraph (c) of this Rule.

(e) A vessel towed or if more than one vessel is being towed the last vessel of the tow, if manned, shall at intervals of not more than 2 minutes sound four blasts in succession, namely one prolonged followed by three short blasts. When practicable, this signal shall be made immediately after the signal made by the towing vessel.

(f) When a pushing vessel and a vessel being pushed ahead are rigidly connected in a composite unit they shall be regarded as a power driven vessel and shall give the signals prescribed in paragraphs (a) or (b) of this Rule.

(g) A vessel at anchor shall at intervals of not more than 1-minute ring the bell rapidly for five seconds. In a vessel 100 meters or more in length the bell shall be sounded in the forepart of the vessel and immediately after the ringing of the bell the gong shall be sounded rapidly for about 5 seconds in the after part of the vessel. A vessel at anchor may in addition sound three blasts in succession, namely one short, one long and one short blast, to give warning of her position and of the possibility of collision to an approaching vessel.

(h) A vessel aground shall give the bell signal and if required the gong signal prescribed in paragraph (g) of this Rule and shall, in addition, give three separate and distinct strokes on the bell immediately before and after the rapid ringing of the bell. A vessel aground may in addition sound an appropriate whistle signal.

(i)   A vessel of 12 meters or more but less than 20 metres in length shall not be obliged to give the bell signals prescribed in paragraphs (g) and (h) of this Rule.  However, if she does not, shall make some other efficient sound signal at intervals of not more than 2 minutes.

(j) A vessel of less than 12 metres in length shall not be obliged to give the above-mentioned signals but, if she does not, shall make some other efficient sound signal at intervals of not more than 2 minutes.

(k) A pilotage vessel when engaged on pilotage duty may in addition to the signals prescribed in paragraph (a), (b) or (g) of this Rule sound an identity signal consisting of four short blasts.

Fog signals must be made, when operating in or near, an area of restricted visibility and especially when approaching such an area.  However, the density of fog, which necessitates the use of fog signals, has not been defined.  It is argued that there is little point in generating sound signals, when the actual visibility is equal to, or greater, than the audible range of the sound signals being used.  But if the visibility is reduced, then it would be prudent to operate the sound signals in accordance with the practice of good seamanship (i.e. are you in the open ocean or in coastal/pilotage waters) as it gives small vessels, ample warning of your approach.

Some students have found it easier to equate the sound signals to their morse code counterparts.  This only works for some of the signals, such as “Delta” and “Charlie” and to avoid confusion, it is always recommended to remember the signals as being entirely separate from their morse meanings.

Paragraph (c) and (d) can be summed up as

“Vessels that are:-

1.     RAM

2.     NUC

3.     Constrained by their Draught

4.     Towing Vessels

5.     Fishing Vessels

6.     Sailing Vessels

Shall sound one prolonged blast followed by two short blasts, at intervals not exceeding 2 minutes.”

Note here, that the towing vessel does not have to be Restricted in its Ability to Manoeuvre as defined in Rule 3 (g), as the above whistle signal is to be given by any vessel engaged in towing any other vessel.

Paragraph (h) (vessels aground) has also been found to give great trouble with students remembering the correct sequence.  In short, it is 3 distinct strokes on the bell, rapid ringing of the bell for 5 seconds, 3 distinct strokes on the bell, rapid ringing of the gong in the afterpart (if the length of vessel requires it – i.e. greater than 100m in length) for 5 seconds.  This signal is to be given at intervals not exceeding 1 minute.  The appropriate whistle signal is not defined, but it is suggested that Uniform – you are running into danger i.e. two short blasts followed by one prolonged blast, would appropriately warn other vessels in the vicinity of your predicament and the inherent danger of them also running aground.

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