94 R'EPOET OF COMMISSIONER OF FISH AND FISHERIES. [92]; 



/. Arm. 



g. Eyebolt. 



li. Sinker. 



L Dredge rope. 



j. Dredging block. 



k. Dredging boom. 



DIMENSIONS. 



Bow (steel): 



Diameter, 11 inches. 



Width at center, 3 inches. 



Width at ends, 2^ inches. ' 



Thickness at ends, one-half inch. 



Thickness at center, one-fonrth of an inch. 

 Tangle bars (iron) : 



Length, 5 feet. 



Width, 2-J inches. 



Thickness, one-half inch. 



Number of holes for tangles, 5. 



Diameter of holes, live-eighths of an inch. 

 Eyebolts for tangles (iron), diameter, one-fourth of an inch. 

 Tangles (hemp), lengthy 4 feet. 

 Tangles (beckets), 21-thread ratlin stuff. 

 Arm (mild steel) : 



Semi-circula*, diameter, 1 foot 6 inches. 



Width of metal, 2^ inches. 



Thickness of metal, one-half inch. 

 Eyebolt (iron), diameter of metal (square), five-eighths of anLaoh. 

 Sinker (cast-iron) : 



Diameter, 9 inches. 



Weight, 150 pounds. 



The first tangle of this form was improvised at sea, after expending 

 the last tangle bar, by bending a bar of iron in the form of a V, the 

 tangles being seized to a 3-inch rope, which was drawn around the 

 frame and secured to it by lashings. It worked so well that we used it 

 the remainder of the cruise and finally adopted the present form. 



The bow a is made of spring-tempered steel and permits the bars 

 to close with a pressure of between 300 and 400 pounds applied to their 

 extremities, so that the apparatus will pass between rocks or other ob- 

 structions which permit the passage of the bow and sinker. 



Each tangle is secured to its bar by a one-fourth inch eyebolt, which 

 draws at a tension of about 1,000 pounds, releasing its tangle when 

 irretrievably fouled on the bottom without endangering the loss of the 

 whole apparatus. The tangle bars were made separately from the bow 

 and attached by bolts and nuts at e to secure better stowage and make 

 the parts lighter to handle. The semicircular arm / is intended to raise 

 the forward end of the tangle frame a few inches off the bottom ; also to 

 act as a shoe in dragging over rocks or other uneven surfaces. It is 

 held in position by the eyebolt g, which is square and fits snugly in 

 square holes in the arm and bow. 



The tangles are, in material, size, and structure, practically the same 

 as the deck swabs in general use on board ship. 



