296 



DREDGING AND TRAWLING 



and the procedure in shooting and hauling is very 

 complicated. Yachtsmen will find patterns with a 

 15 to 30 feet beam amply large enough. In these 

 sizes the shooting and hauling does not present any 

 considerable difficulty. 



FIG. 200. BALL DREDGE. 

 (AFTER WYVILLE THOMSON.) 



FIG. 201. AGASSIZ TRAWL, 

 " BLAKE " PATTERN. 



The beam trawl is towed by a pair of spans which 

 are shackled to eyes in the front of the heads. Each 

 span should be three and a half or four times the length 

 of the beam, and as stout as the warp. The head rope 

 of the net is as long as the beam, and is laced to it. 



