2. PLANS AND PREPARATIONS 



31 



on surveying operations, shall have at hand 

 and show, if necessary in order to attract 

 attention, a flare-up light in addition to the 

 lights which are, by this section, required to 

 be carried. 



(b) International Rules of the Road. — A 

 vessel engaged in surveying or underwater 

 operations when from the nature of her work 

 she is unable to get out of the way of ap- 

 proaching vessels, shall carry in lieu of the 

 white range or masthead lights, three lights 

 in a vertical line, one over the other, not 

 less than 6 feet apart. The highest and 

 lowest of these lights shall be red, and the 

 middle light shall be white, and they shall 

 be of such a character as to be visible all 

 round the horizon at a distance of at least 

 2 miles. By day, she shall carry in a vertical 

 line one over the other and not less than 6 

 feet apart, where they can best be seen, three 

 shapes each not less than two feet in diameter, 

 of which the highest and lowest shall be 

 globular in shape and red in color, and the 

 middle one diamond in shape and white. 



These signals indicate that the vessel is 

 not under command, and cannot get out of 

 the way of approaching vessels. When it is 

 apparent that an approaching vessel does not 

 heed the signals displayed by the survey 

 vessel, the danger signal should be sounded 

 by the survey vessel. 



A vessel engaged in surveying or under 

 water operations, when at anchor, shall carry 

 the lights or shapes prescribed above in ad- 

 dition to the anchor lights or shape required 

 by the rules. 



A survey vessel underway on a sounding 

 line at night shall show the lights, prescribed 

 for a vessel of her size ; and when at anchor 

 and not engaged in survey operations shall 

 show only the anchor lights or shape pre- 

 scribed for a vessel of her size. 



2-33 Small-boat landings. — There is per- 

 haps no one phase of seamanship so es- 

 sential in hydrographic surveying as com- 

 petency in handling small boats and making 

 landings on exposed coasts. Most hydro- 

 graphic surveys consist of operations along 

 the coastal area where the sea meets the 

 shore, and where the greatest danger lies. 



The very nature of the operations requires 

 the use of small boats and repeated landings 

 on the shore. An important feature of the 

 training of new members of a crew at the 

 beginning of each field season is to famil- 

 iarize them with these duties and to provide 

 every opportunity for them to acquire prac- 

 tice. 



Officers and a crew who are experienced 

 lifeboatmen and seamen are essential in 

 hydrographic surveying, but it must not be 

 assumed that one who is an otherwise com- 

 petent seaman has the knowledge and ex- 

 perience required to make small-boat landings 

 under dangerous conditions. This is an art in 

 itself, requiring a special knowledge and skill 

 only acquired by practical experience and 

 which many seafaring men never have 

 occasion to practice. When undertaken by 

 the inexperienced, the danger involved can 

 scarcely be overestimated. 



The subject is adequately treated, insofar 

 as practicable in text, in many treatises on 

 seamanship, and these should be studied 

 thoroughly and reviewed at the start of each 

 field season. The rules published by the Royal 

 National Lifeboat Institution on the subject 

 are very helpful. An almost infinite variety 

 of conditions may be encountered, and the 

 method adopted must vary to meet them 

 successfully. This Manual can only emphasize 

 the importance of the following in connection 

 with small - boat landings under diflScult 

 conditions: 



Use only experienced personnel. 



Conditions never appear as dangerous 

 from seaward as they really are. 



Always use a steering oar, never a rudder. 



Keep the boat under control at all times. 



The outermost of a series of breakers 

 is much the heaviest. 



In a strange locality, lie-to outside the 

 breakers to study the particular con- 

 ditions before attempting a landing. 



The one great danger, when running 

 before a broken sea, is that of broach- 

 ing-to. 



A number of heavy swells are often 

 followed by a short and comparatively 

 mild interval. 



