[83] U. S. FISH COMMISSION STEAMER ALBATROSS. 85 



of a slack line, to prevent the upper part of the bag from falling and 

 obstructing the mouth while dragging. 



The bridle is practically the same as suggested by Sigsbee. Large 

 eyes are spliced in the ends of a 3-inch rope, a thimble turned in the 

 middle, and an overhand knot taken in each leg at the point of contact 

 with the eyebolts on the front of the runners. Seizings are passed 

 •through the eyebolts and around the bridle legs forward of (he knots, 

 and the ends of the legs are securely lashed to the tail of the trawl net. 

 Should the trawl foul on the bottom or take in a dangerously heavy 

 load it is intended that the seizings shall part, and the. trawl be drawn 

 up tail foremost. The strength of seizings required for this purpose at 

 the forward end of the runners is determined by experiment. 



We have used the trawl described above with good results in deep 

 water. It is not, however, adapted for use on the hard sandy bottom 

 usually encountered in shoal water, for the reason that sufficient sweep 

 cannot be given the lead rope. It has another fault which has prac- 

 tically driven it out of use on board of this vessel. It will be seen by 

 reference to the plate that the mouth of the trawl will be extended 

 equal to the depth of the runners while being hove up; consequently 

 the wash of water through the meshes of the net must be very great ; so 

 great, in fact, that in a sea-way it often seriously injured the specimens. 



BEAM TEAWL. 



The beam-trawl frame, Plate XLVII, shows the form in use on board 

 of this vessel, both for shoal and deep-water work. 



The following are the dimensions of the frame and net : 

 Beam: 



Iron pipe, length, 11 feet. 



Outside diameter, 2-J inches. 



Thickness of metal, -,% inch. 

 Collars, brass, width, 4 inches ; thickness, f inch ; length of flange, 9} inches ; di- 

 ameter of bolts, £ inch. 

 Runners : 



Length, 5 feet. 



Height, 2 feet 5 inches + 4 inches ; total, 2 feet 9 inches. 



Width, 4 inches. 



Thickness of metal, f inch. 

 Weight of trawl frame, 365 pounds. 

 Rope for bridle, 3 inches. 

 Rope for lead rope, 2 inches. 

 Rope for head rope, 1-J inches. 

 Trawl net : 



Length, 17 feet. 



Size of mesh, square, 1 inch. 



Material, cotton, barked, 30-thread. 



Pocket, length, 6 feet. 



Pocket, size of mesh, square, 1 inch. 



Pocket, materia], cotton, barked, 21-thread. 



Jacket, length, 6 feet. 



Jacket, size of mesh, square, ^ inch. 



Jacket material, cotton, barked, 16-thread. 

 Bottom lining of cheese-cloth for deep-water work. 



