RAFTING 



413 



fastened and between the boi'e-holes in them, the thin end of a 



withe is passed through (a b) over the pole, and then into (c). 



The thick end of the withe gets jammed in (a h), and the thin 



end is fixed in (c d) by means of a 



Avooden wedge. Instead of withes, Fm. 243. 



the poles may be fastened to each i0^e 



log by iron nails or clamps. In this 



method the raft-section is a rigid 



body, and no independent motion 



is allowed to the individual logs. 



This mode of fastening has the 

 great advantage, that the logs are much less injured by the bore 

 holes than by the larger holes made in the former case. In 

 that case, the ends* of the logs must be sawn-off, whilst when 



Fig. 244. 



the pole is used, the bore-hole can be eventually plugged with 

 a piece of wood and the whole log become utilizable. 



In powerful streams with numerous rapids, as in the river 

 Isar, the poles are sometimes let into the logs. The latter are 

 grooved at their ends, so as to admit the pole, and then fastened 

 to it as before. The raft-section thus fastened is more rigid and 

 stronger than without the groove. In Moravia, only the outer 

 logs are grooved, and trenails are used to fix the pole to the 

 logs (fig. 244). 



The first condition for rafting is that the wood to be rafted is 

 lighter than water, which is the case with all German woods 



* These separate ends ot" floated logs are used in many places for pavin 

 stables. 



