150 



HYDROGRAPHIC MANUAL 



charge of a watch aboard ship or of a launch 

 hydrographic party is responsible for the 

 adequacy of the survey operations and the 

 safety of the vessel. He issues all necessary 

 orders, supervises, and inspects the work of 

 the other members of the survey party. 



It is customary for the officer-in-charge to 

 plot the positions on the boat sheet, issue 

 orders to the helmsman, determine the inter- 

 vals between soundings and positions, and 

 select the objects to which sextant angles 

 are to be taken. He may observe one of the 

 angles, preferably the left. Junior officers 

 assigned to the watch or party should be 

 trained in all phases of the operation includ- 

 ing position plotting. There may be some 

 confusion and loss of time while young offi- 

 cers learn these various duties, but the train- 

 ing of junior officers is one of the primary 

 duties of senior officers and must not be 

 neglected. 



5-53 Anglemen and Shoran observers. — 



The anglemen observe the sextant angles for 

 the fixed positions in three-point fix control. 

 One officer may observe the left angle and 

 plot positions; however, when qualified ob- 

 servers are available, it is better to have two 

 anglemen so that the plotter may devote 

 more time to supervision of other operations. 

 When signals are distant or faint, or if fixes 

 are required at very short intervals, two 

 anglemen in addition to the officer-in-charge 

 are necessary. One angleman should be a 

 junior officer or a petty officer, and the other 

 may be any member of the complement who 

 has been trained to use a sextant. Both 

 anglemen should act as lookouts when not 

 taking an angle. They should report the 

 presence of kelp, current streaks or eddies, 

 breakers, buoys, rocks, etc. The left angle- 

 man may select the objects to be used in the 

 fix. One angleman assists the coxswain to 

 lower and raise the bar when bar checks are 

 being made by a launch. 



When Shoran is used for control of the 

 hydrography, one observer is required to at- 

 tend the instrument and measure the Shoran 

 distances. If the sounding lines are being 

 run along distance arcs, he issues orders for 

 changes of course to maintain the required 



PERSONNEL 



In Charge U. A . Sha,rp 



J32.U 



Cor, 



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oxr 



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sjc 



iJ.A. S. 



L Angle ^. C /IneirsliJS Se«tant No . 



R Angle A. A/. S-^nnf>. SextanI No 



Recorder l/. C /Cfi//tJ Clock No 



At Echo Sn.jnrter I J. P. fjUJeD 



Leadsman </. P. O. Leadlrne No ^ 



Figure 56. — Personnel stamp for sextant controlled 

 hydrography. 



spacing. This duty should be shared by two 

 observers alternately standing a watch of 

 one to two hours at the Shoran indicator. 

 When qualified, they should give occasional 

 temporary relief to the recorder or echo 

 sounder observer (see 2-18) . 



5—54 Recorder. — A competent recorder 

 must be thorough, conscientious, accurate, 

 and not easily rattled by confusion occa- 

 sionally arising from a rapid series of events 

 which must be recorded, and he must be 

 familiar with the requirements of pertinent 

 parts of this manual. 



The official written record and notes of 

 the hydrographic survey are kept by the 

 recorder. He records the soundings as re- 

 ported by the echo sounder operator, the 

 sextant angles or other control data, and 

 the times of these events. He also records 

 changes of course, except when following 

 distance arcs, and records pertinent notes in 

 the remarks column, such as changes in 

 speed; the beginning and ending of lines; 

 references to adjacent features as rocks, 

 breakers, or aids to navigation ; changes in 

 equipment or personnel ; and other notes nec- 

 essary for correct interpretation of the sur- 

 vey data. All entries must be clearly legible. 



After the regular intervals between sound- 

 ings and positions have been ordered, the 

 recorder is the one who sees to it that the 

 soundings and positions are taken at the 

 specified times. The recorder repeats aloud 

 all data which are called out to him to be 

 recorded. 



The recorder, with the assistance of an- 

 other member of the hydrographic party, 

 shall verify the length and markings on the 

 lines attached to the bar check at least once 

 each week and enter the results in the sound- 

 ing record (see 3-109). On days when a 



