than two minutes, two prolonged blasts, with an interval of about one second between them.
(c) A sailing vessel under way shall sound, at intervals of not more than one minute, when on the starboard tack one blast, when on the port tack two blasts in succession, and when with the wind abaft the beam three blasts in succession.
(d) A vessel, when at anchor, shall, at intervals of not more than one minute, ring the bell rapidly for about five seconds.
(e) A vessel when towing, a vessel employed in laying or picking up a telegraph cable, and a vessel under way, which is unable to get out of the way of an approaching vessel through being not under command, or unable to manœuvre as required by these rules, shall, instead of the signals prescribed in subdivisions (a) and (c) of this Article, at intervals of not more than two minutes sound three blasts in succession, viz. one prolonged blast followed by two short blasts. A vessel towed may give this signal, and she shall not give any other.
Sailing vessels and boats of less than 20 tons gross tonnage shall not be obliged to give the above-mentioned signals, but if they do not, they shall make some other efficient sound signal at intervals of not more than one minute.
SPEED OF SHIPS TO BE MODERATE IN FOG, ETC.
Art. 16. Every vessel shall, in a fog, mist, falling snow, or heavy rain-storms, go at a moderate speed, having careful regard to the existing circumstances and conditions.
A steam vessel hearing, apparently forward of her beam, the fog-signal of a vessel the position of which is not ascertained, shall, so far as the circumstances of the case admit, stop her engines, and then navigate with caution until danger of collision is over.
