Page 179 control and signal building 2841 



sitivity of the sound receiver may be adjusted without removing the entire cover. There are two 

 other threaded openings in the head of the barrel, on opposite sides of the 15-inch cover, fitted with 

 1-inch packing glands. The hydrophone lead passes through one of these openings and the antenna 

 lead through the other. When the sono-radio buoy is assembled the radio equipment is attached to 

 the underside of the cover, and the batteries, packed securely in a wooden rack of circular shape, are 

 placed in the bottom of the barrel and held in place by wooden wedges. 



The large barrel is held in the frame by means of two semicircular iron straps around the barrel 

 near its top, bolted to the frame with through bolts. Two wooden cross braces, notched to fit the 

 chimes, are nailed to the two sides of the frame to hold the bottom of the large barrel in place. The 

 small barrel is placed below the large barrel, the undersides of the same cross braces being notched to 

 fit its chimes. The lower end of the small barrel is held by the tie rod which is drawn tight enough 

 to hold it securely in the frame. 



The vertical frame is extended 6 feet above the top of the barrel by two pieces of 2- by 4-inch lum- 

 ber nailed on each side. To each of these is bolted a piece of 1- by 4-inch lumber to support the 

 antenna mast. The mast may be made of either 1- by 4- or 2- by 4-inch lumber held in place between 

 its supporting pieces by bolts. The antenna is secured to the narrow edge of the mast by means of 

 screw-type house bracket insulators. The entire antenna assembly is bolted to the frame so that it 

 may be detached. The rope hoisting sling and the eyebolt, to which the anchor cable is attached, are 

 assembled as explained in 2824(C). 



A 2- by 4-inch crosspiece is nailed across the upper ends of the two 2- by 4-inch lower frame 

 members just above the upper tie rod. This crosspiece serves to support a watertight box containing 

 the antenna coupler, high enough so that it will not be submerged. ^ 



The hydrophone is suspended by a ^i-inch flexible copper cable from a 2- by 4-inch crosspiece 

 nailed on the lower frame 2 feet above the top of the counterweight. The hydrophone lead is secured 

 to the wood frame by brass clamps (although not so shown in the figure) and extends to the hydro- 

 phone with sufficient slack so that the weight of the hydrophone is not suspended on the lead. Both 

 the copper cable and hydrophone lead are enclosed in a section of discarded rubber hose which protects 

 them from chafing. The hose is secured to the lower end of the counterweight. 



Flags and screen-wire banners should never be used on sono-radio buoys, because 

 if either touches the antenna, the circuit is affected. Small crossed banners made of 

 cloth, not larger than 18 inches square, may be used. They should be nailed to the mast 

 so they do not touch the antenna, and the cloth should be secure enough so that there 

 is no likelihood of it tearing and being blown against the antenna. Banner masts 

 should not be attached above the antenna masts, because the added strain may break 

 the antenna mast. 



(B) LIST OF MATERIALS* FOR EAST COAST SONO-RADIO BUOY 



Number 

 Description Size required 



Lumber (see 281).. 2" by 4" by 18' 4 pieces. 



Lumber (see 281) 2" by 4" by 16'.. 2 pieces. 



Lumber (see 281) 1" by 4" by 16' 2 pieces. 



Lumber (see 281) 1" by 4" by 10' 1 piece. 



Wedges, wooden to fit 2 each. 



Barrel, G. I., with special removable head 65 gallons, 22" diameter... 1 each. 



Barrel, Q. I 30 to 35 gallons, 18" diameter leach. 



Car coupler Weight added to make 250 pounds 1 each. 



Bolts, with hexagonal nuts . W by 16" 2 each. 



Washer plates 3" by 5" by W', drilled for H"bolt 4 each. 



Strap, bent to fit semicircumference of large barrel.. 2" by H" by 36" 2 each. 



Rod, tie, threaded both ends ^" by 26H" 1 each. 



Rod, tie, threaded both ends H" by 28" 1 each. 



Bolts y^" by 6" 4 each. 



Bolts H"by4" 7 each. 



Bolts, with countersunk head W' by 4" 4 each. 



Nuts, hexagonal H" 19 each. 



Washers lH"byM6" (9^6" hole) 22 each. 



Eyebolt, with hexagonal nut and washer ?4" by 6" 1 each. 



Nails 12 d. and 20 d. 



Rope, Manila 4" 15 feet. 



Standard enameled buoy plate 1 each. 



