Page 163 control and signal building 281 



The kind of lumber to be used in buoy construction is limited by what is locally 

 available. It should be a first-quality, straight-grained wood, free from knots and 

 checks, light in weight but structurally strong, thorouglily air dried, either rough or 

 surfaced. The best lumber available on theAtlantic and Gulf Coasts is Southern cypress, 

 while Douglas fir and redwood are to be preferred on the Pacific Coast. Because the 

 life of a survey buoy is comparatively short, common nails, and ordinary steel screws, 

 machine bolts, and plates are used in its construction. 



Standard commercial steel drums and barrels are used almost exclusively to give 

 buoyancy to the buoy structures. The returnable or nonreturnahle steel, oil, or gasoline 

 barrels of 55-gallon capacity are generally used for ordinary buoy structures. A 65- 

 gallon barrel, equipped with a bolted cover, is used in the East Coast sono-radio buoy, 

 and a 55-gallon removable top, bilge barrel is used for the Vincent type. Steel barrels 

 of various sizes down to 10-gallon capacities are used in combination with the larger 

 barrels. These smaller barrels are also used in constructing small buoys. Spherical 

 steel buoys of small size will be found useful for various field operations. 



Recent experiments with buoys indicate that better buoyancy may be provided 

 by a specially designed buoy (see 2843) . A single bare 55-gallon barrel anchored in 

 50 fathoms of water with the usual anchor cable has a reserve buoyancy of only 177 

 pounds and the Vincent sono-radio buoy without anchor cable has a reserve buoyancy 

 of only 200 pounds. A relieving buoy should always be used to support the anchor 

 cable of a sono-radio buoy in areas where there are strong currents — the reserve buoy- 

 ancy is not sufficient to depend on in such cases. 



The most essential feature of a drum or barrel for use in buoy construction is its 

 watertightness. It should also be of strong but light construction so as not to add 

 unduly to the total weight of the buoy. The use of a standard commercial product is 

 an economy. 



The ordinary crossed targets on a buoy structure may be made of signal cloth, 

 ordinary screen-wire cloth, or board slats. Screen-wire cloth has been found to be 

 more durable, black preferred for visibility. If black is not available, screen painted 

 black is satisfactory. Flags and large banners are made of a suitable grade of cloth. 

 Colors in varying combinations are used to identify the buoys. The banners, flags, 

 and targets are constructed to be attached to the buoy at the last moment, and to be 

 readily detached when it is brought aboard, to facilitate stowage in a smaller space. 

 Where subtended vertical angles (see 3363) may need to be observed on buoys, all 

 crossed banners on either survey buoys or sono-radio buoys should be placed at a 

 known height above the waterline. 



The counterweights may be any heavy metal pieces of small bulk procured from 

 junk yards. The total weight of the counterbalance required depends on the size and 

 design of the buoy. For the standard one-barrel buoy, a single railroad car coupler, 

 weighing from 180 to 200 pounds, is most satisfactory. A precast concrete shape of 

 suitable size and weight may also be used. The counterweight should be made to be 

 readily attached and detached from the buoy structure. 



Buoys are painted to afford greater visibility and for preservation. The superstruc- 

 ture above the barrels is generally painted with a good grade of exterior paint, the color 

 to be used being selected to afford the greatest visibility; in hazy atmosphere white 

 will generally prove best, while red or black is best where clear atmospheric conditions 

 prevail. The barrels and all of the underwater parts of the buoy are generally painted 

 with either red lead or antifouling paint. 



