410 



WOOD TRANSPORT BY WATER. 



former class of rafts is in use in the upper and middle courses 

 of rivers and brooks, whilst the latter is employed on broad, 

 steadily flowing streams. 



The former kind of rafts may, however, be very long, and 

 often consist of from 40 to 70 sections hung one behind the 

 other, containing altogether 300 to 500 logs and more. The 

 large rafts, on the other hand, are often 50 meters (160 feet) 

 broad and 200 to 250 meters (650 to 810 feet) long, and were 

 formerly even larger. 



4. Mode of Rafting. 



A raft should be conducted so that it can be guided, its pace 

 moderated, or it can be stopped at pleasure. On slowly 



Fig. 281. End section of raft. 



flowing waters, ordinary spreads are used to guide the rafts. 

 Where the current is rapid the rafts are made long so that 

 they may travel slowly, and spreads are hung out behind the 



last section to drag 

 along the bottom of the 

 channel ; the last sec- 

 tion may also be opened 

 out as in Fig. 281, or 

 a kind of brake is used 

 from the last section as 

 shown in Fig. 282 in sec- 

 tion and Fig. 283 in plan. 



This brake consists of a stout beam (a) passing between two 

 poles (b) fastened to the raft by clamps, or withes. The brake 

 drags obliquely along the bottom of the channel, whilst it is 

 firmly held above between the poles. In this way the pace of 

 a raft may be regulated, and the raft directed through difficult 

 passages and even stopped or stranded. Long heavy rafts on 



