48 LAWS GOVERNING MARINE INSPECTION 



(vi) The International Code Signal of distress indicated by 

 N.C. 



(vii) A signal consisting of a square flag having above or below 

 it a ball or anything resembling a ball. 



(viii) Flames on the vessel (as from a burning tar barrel, oil 

 barrel, &c.). 



(ix) A rocket parachute flare or a hand flare showing a red 

 light. 



(x) A smoke signal giving off a volume of orange-coloured 

 smoke. 



(xi) Slowly and repeatedly raising and lowering arms out- 

 stretched to each side. 

 Note. — Vessels in distress may use the radiotelegraph alarm signal 

 or the radiotelephone alarm signal to secure attention to distress calls 

 and messages. The radiotelegraph alarm signal, which is designed to 

 actuate the radiotelegraph auto alarms of vessels so fitted, consists of 

 a series of twelve dashes, sent in 1 minute, the duration of each dash 

 being 4 seconds, and the duration of the interval between 2 consecutive 

 dashes being 1 second. The radiotelephone alarm signal consists of 

 2 tones transmitted alternately ovet periods of from 30 seconds to 

 1 minute. 



(b) The use of any of the foregoing signals, except for the purpose 

 of indicating that a vessel or seaplane is in distress, and the use of 

 any signals which may be confused with any of the above signals, 

 is prohibited. 



Annex to the Rules 



recommendations on the use of radar information as an aid to 

 avoiding collisions at sea 



33 U.S.C. 1094 



(1) Assumptions made on scanty information may be dangerous 

 and should be avoided. 



(2) A vessel navigating with the aid of radar in restricted visibility 

 must, in compliance with Rule 16(a) , go at a moderate speed. Infor- 

 mation obtained from the use of radar is one of the circumstances to be 

 taken into account when determining moderate speed. In this regard 

 it must be recognised that small vessels, small icebergs and similar 

 floating objects may not be detected by radar. Radar indications of 

 one or more vessels in the vicinity may mean that "moderate speed" 

 should be slower than a mariner without radar might consider mod- 

 erate in the circumstances. 



(3) When navigating in restricted visibility the radar range and 

 bearing alone do not constitute ascertainment of the position of the 

 other vessel under Rule 16(b) sufficiently to relieve a vcssel of the 

 duty to stop her engines and navigate with caution when a fog signal 

 is heard forward of the beam. 



(4) When action has been taken under Rule 16(c) to avoid a close 

 quarters situation, it is essential to make sure that such action is having 

 the desired effect. Alterations of course or speed or both are matters 

 as to which the mariner must be guided by the circumstances of the 

 case. 



