398 LOGGING 



pulpwood/ and, when built of large size, for saw logs.- With a 

 backbone it requires less water than any other type. 



A box with a vertex angle of 90 degrees is regarded as the 

 most desirable since this angle permits the cheapest construction 

 because the joints can be fitted more easily and the lumber used 

 to better advantage. 



An objection sometimes raised to the use of a V-box for the 

 transport of shingle bolts and like material is that the individual 

 pieces are uneven in size and weight and do not all travel at the 

 same speed, therefore they are apt to double on low grades and 

 on curves. 



The V-flume with a backbone is considered the more desirable 

 form for a mixed cut of lumber and dimension stock. The 

 capacity of a flume of this character does not exceed 100,000 

 feet daily, with an average of from 40,000 to 50,000 feet. 



The box of a V-flume for lumber and crossties has sides 

 ranging from 15 to 18 inches high and is from 30 to 36 inches 

 wide at the top (Fig. 123, yl and B). The backbone when added 

 is made from a 6- by 6-inch or 8- by 8-inch timber sawed 

 diagonally. The side boards of the box are i inch in thickness 

 for sides up to 30 inches in height, i| inches if from 30 to 

 36 inches high, and 2 inches if from 36 to 48 inches high. 

 The cracks are battened with i- by 4-inch or i- by 6-inch strips. 

 The boards range in width from 8 to 14 inches, but are usually 



1 A pulpwood flume operated in the Adirondack Mountains of northern New 

 York was 36 inches across the top and 36 inches deep. It was supported on a 

 trestle which in places was 100 feet high. The flume was af miles long, had a 

 capacity of sixty cords of 18-inch pulpwood per hour, and the bolts traversed the 

 distance in 7I minutes, dropping into a stream down which they were driven to 

 a pulp mill. 



2 A 5-mile log flume (Fig. 123, D) was recently constructed in Idaho with an 

 average grade of 11 per cent, a maximum grade of 15 per cent, and a maximum 

 curvature of 20 degrees. The box was supported on trestles 16 feet apart with 4- by 

 8-inch sills, posts, and caps and 2- by 6-inch braces; 5- by lo-inch stringers with 

 2- by 6-inch lateral braces and round pole supports in the center of each bent; 

 4- by 6-inch bracket sills spaced from 2 to 4 feet apart depending on the weight 

 carried and the strength required at loading points, and 3- by 6-inch braces. The 

 box was made from 2-inch rough lumber with the cracks battened with ij- by 

 4-inch strips. The cost of the flume complete was about $8,000 per mile. See 

 The Timberman, August, 1912, pp. 42-44- See note on page 411. 



