42 LAWS GOVERNING MARINE INSPECTION 



of visibility of lights or shapes, without interfering with the military 

 function or the vessel or seaplane, such vessel or seaplane shall comply 

 with such other provisions in regard to the number, position, range or 

 arc of visibility of lights or shapes as her Government shall have 

 determined to be the closest possible compliance with these Rules in 

 respect of that vessel or seaplane. 



33 U.S.C. 1074 (Rule 14) 



A vessel proceeding under sail, when also being propelled by 

 machinery, shall carry in the daytime forward, where it can best be 

 seen, one black conical shape, point downwards, not less than 2 feet 

 in diameter at its base. 



Part C. — Sound Signals and Conduct in Restricted 

 Visibility 



preliminary 



33 U.S.C. 1075 



l.Tlie possession of information obtained from radar does not 

 relieve any 'vessel of the obligation of conforming strictly with the 

 Rules and, in particular, the obligations contained in Rules 15 and 16. 



2. The Annex to the Rules contains recommendations intended 

 to assist in the use of radar as an aid to avoiding collisions in restricted 

 visibility. 



33 U.S.C. 1076 (Rule 15) 



(a) A power-driven vessel of 40 feet or more in length shall be 

 provided with an efficient whistle, sounded by steam or by some sub- 

 stitute for steam, so placed that the sound may not be intercepted by 

 any obstruction, and with an efficient fog horn to be sounded by 

 mechanical means, and also with an efficient bell. A sailing vessel 

 of 40 feet or more in length shall be provided with a similar fog horn 

 and bell. 



(b) All signals prescribed in this Rule for vessels under way shall 

 be given — 



(i) by power-driven vessels on the whistle; 



( ii ) by sailing vessels on the fog horn ; 



(iii) by vessels towed on the whistle or fog horn. 



(c) In fog, mist, falling snow, hea^'y rainstorms, or any other 

 condition similarly restricting visibility, whether by day or night, 

 the signals prescribed in this Rule shall be used as follows — 



(i) A power-driven vessel making way through the water 

 shall sound at intervals of not more than 2 minutes a prolonged 

 blast. 



(ii) A power-driven vessel under way, but stopped and making 

 no way through the water, shall sound at intervals of not more 

 than 2 minutes two prolonged blasts, with an interv^al of about 

 1 second between them. 



(iii) A sailing vessel under way shall sound, at intervals of 

 not more than 1 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. 



