58 HYDROGRAPHICAL SURVEYING [ciur. i. 



Weighing is accomplished best from the foreyard. Having 

 hooked to the weighing strop, run the beacon up, and having 

 made fast a hne from the hawse pipe to the wire strop at the 

 upper end of mooring chain, knock off the shp, when the 

 beacon can be landed inboard, and the mooring run up to the 

 hawse pipe. 



Care is necessary to approach the beacon from the proper 



direction relatively to the wind and current, so that the ship 



will lie in the direction of their resultant, and thus avoid 



bringing undue strain on the moorings. 



Fixed ^ fixed beacon can be erected in shallow water of from 



Beacon. 



2 to 3 fathoms by constructing a tripqfl of spars of about 



45 feet long. The heads of two of them are lashed together, 

 and the heels kept open at a fixed distance by a plank about 

 27 feet long nailed on about 5 feet above the heels of the span. 

 These are taken out by three boats, and the third tripod leg 

 lashed in position on the boats, the heel in the opposite direc- 

 tion to the two others. The legs are weighted, and a gantline 

 block lashed to the fork. The two first legs are let go first 

 together, and the tripod hauled into position by guys. Weights 

 can be added by slipping them down the legs, and the guys 

 secured to anchors. 



A vertical pole with bamboos can now be added, its weighted 

 heel on the ground. It is placed by a jigger from the fork, 

 to which it is afterwards lashed, and guys taken from the 

 lower part to the tripod legs. A block and halliards from 

 the bamboo permits a cahco flag 14 feet square to be hoisted. 



