FLOATING AND RAFTING 391 



a breadth of from 50 to 60 feet. The taper extends 100 feet 

 from each end. 



Ocean-going rafts are built in a cradle or frame which is 

 moored to piling in deep water. One side of the cradle is de- 

 tachable and when the raft is completed it is launched by dropping 

 this side and allowing the raft to slide sidewise into the water. 

 A 700-foot cradle requires 200,000 feet of timber in its construc- 

 tion, and costs about $5000. With minor repairs it can be used 

 for an indefinite period. A derrick hoisting engine, mounted 

 on a scow, and valued at $5000 is necessary for stowing logs in 

 the cradle. A crew of five or six raftsmen is required. 



The logs are floated out to the cradle and, beginning at either 

 end of the latter, the longest and most pliable sticks are used 

 for the outer layers. These sticks should be at least 60 feet 

 long and are placed with their butts toward the center of the 

 raft. This gives a taper to the body of the raft and as the logs 

 gradually work outward the binding chains are drawn tighter. 

 The interior may be filled with any length logs, provided the 

 joints are broken. 



After the raft has been built up to a height of 20 feet, a 21- 

 inch tow chain is laid from stem to stern with 50 feet projecting 

 on either end to which the towing cable is attached. "Herring 

 bone" chains, made from if -inch iron, are then attached to 

 the main tow chain on the tapering ends of the raft, run diago- 

 nally across the raft toward either end, and fastened to the bind- 

 er chains. This prevents the latter from slipping on the conical 

 portion of the raft, distributes the pull of the tow chain over 

 a large portion of the stern, and also gives a limited amount of 

 slack in the center, which is essential to permit the raft to bend 

 slightly with the action of the waves. 



When the raft is completed, binder chains made from if-inch 

 iron are placed entirely around it at 12-foot intervals and are 

 tightened by the hoisting engine. A 700-foot raft containing 

 from 4,000,000 to 5,000,000 feet requires about 115 tons of 

 chain, which, with accessories, is valued at $10,000. A 30-foot 

 raft draws from 20 to 22 feet of water and can be towed to 

 San Diego, 1200 miles, for $1 per thousand feet. 



