Page 185 control and signal building 285) 



probably the most favorable conditions in the order of preference, although there is no 

 general agreement as to this: 



(a) Moderate current, no wind, no sea. 



(b) Moderate current, light breeze (in same general direction as current), no sea. 



(c) No current, moderate breeze, little sea. 



(d) No current, no breeze, no sea. 



However, when the direction of the current is at an angle with the direction of a 

 strong wind it is frequently difhcidt and at times impossible to weigh buoys. Under 

 these conditions, the ship should be headed for the buoy in a direction to head into the 

 stronger of the two, or on a heading midway between them. Maneuvers have to be 

 made at a faster speed and more use is made of tVie engine in maintaining the course. 



Where wind-induced currents prevail, for lack of better information, coastal currents 

 may be assumed to set in a direction about 20° clockwise from that direction toward 

 which the wind blows (in the Northern Hemisphere) and in the open ocean about 40° 

 clockwise. For the Southern Hemisphere the differences are in a counterclockwise 

 direction. The rule for coastal currents is not always applicable, especially when near 

 the shore where the direction of the current depends on the angle between the wind 

 direction and the coastline. 



In strong winds and currents the deck force has to act speedily in engaging the 

 buoy and hoisting it aboard. After the buoy is on board, the ship should be held in 

 position over the anchor so that the anchor cable will be approximately vertical while 

 it is being weighed. The anchor cable may lead slightly outboard or fore and aft, but 

 it should never be allowed to lead under the ship because of the strain and danger of 

 parting it. 



It is difficult to substitute one buoy structure for another without disturbing the 

 position of the anchor, particularly when the sea is rough or when the wind and current 

 are in different directions. For this operation it is necessary to hold the ship in position 

 on the required heading for the comparatively long time required to perform the neces- 

 sary operations on deck, without putting any strain on the anchor cable. Only if the 

 heading can be maintained, with the anchor cable hanging almost vertically in the 

 water at all times, is there complete assurance that the anchor has not been dragged 

 from its position. With a twin-screw vessel this operation is performed much more 

 easily than with a single-screw vessel. 



Buoys may be anchored during comparatively rough weather or during periods of 

 poor visibility. Unless it is necessary that they be in alinement, they may be anchored 

 during fog. Even during poor visibility they may be alined satisfactorily for a buoy 

 traverse by the observation of a back bearing on each successive buoy just before it is 

 lost to view, in order to establish the correct course to run to the next. In weighing 

 buoys, fair visibility is required in order to find them, and the sea must not be so rough 

 that it is impossible to come alongside them to hook them with the hoisting line. 



2851. Anchoring Buoys 



The usual method of anchoring buoys in average depths of water for buoy traverses 

 is to lower the buoy structure into the water first, followed by the relieving barrel, if 

 used, with the anchor cable attached. The ship is then allowed to drift, or is backed, 

 slowly away from the buoy as the anchor cable is payed out. The wire rope section 



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