Sound Signals in Restricted Visibility
(1)A power-driven vessel making way through the water shall sound at intervals of not more than two minutes one prolonged blast.
(2)A power-driven vessel underway but stopped and making no way through the water shall sound at intervals of not more than two minutes two prolonged blasts in succession with an interval of about two seconds between them.
(3)A vessel not under command; a vessel restricted in its ability to maneuver, whether underway or at anchor; a sailing vessel; a vessel engaged in fishing, whether underway or at anchor; and a vessel engaged in towing or pushing another vessel shall, instead of the signals prescribed in section (1) or (2) of this rule, sound at intervals of not more than two minutes, three blasts in succession; namely, one prolonged followed by two short blasts.
(4)A vessel towed or if more than one vessel is towed the last vessel of the tow, if manned, shall at intervals of not more than two 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.
(5)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 section (1) or (2) of this rule.
(6)A vessel at anchor shall at intervals of not more than one minute ring the bell rapidly for about five seconds. In a vessel of 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 five seconds in the after part of the vessel. A vessel at anchor may in addition sound three blasts in succession; namely, one short, one prolonged and one short blast, to give warning of its position and of the possibility of collision to an approaching vessel.
(7)A vessel aground shall give the bell signal and if required the gong signal prescribed in section (6) 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.
(8)A vessel of less than 12 meters in length shall not be obliged to give the above-mentioned signals but, if it does not, shall make some other efficient sound signals at intervals of not more than two minutes.
(9)A pilot vessel when engaged on pilotage duty may in addition to the signals prescribed in section (1), (2) or (6) of this rule sound an identity signal consisting of four short blasts.
(10)The following vessels shall not be required to sound signals as prescribed in section (6) of this rule when anchored in a special anchorage area designated by the United States Secretary of Transportation:
(a)A vessel of less than 20 meters in length; and
(b)A barge, canal boat, scow, or other nondescript craft.
Rule 250-011-0220 — Sound Signals in Restricted Visibility,