82 REPORT OF COMMISSIONER OP FISH AND FISHERIES. [80] 



until all the slack is absorbed. This is the one contingency that must 

 be en re fully guarded against in the use of this rope. 



A " long splice" from 20 to 25 feet in length is used to join two pieces 

 of rope. A man with au assistant will make a splice in about two hours, 

 which, if well made, cannot be detected without close observation, and 

 is as strong as other parts of the rope, at least we have found it to part 

 quite as often away from the splices as at them. 



We have used various forms of splice at the end of the rope and have 

 finally settled upon an ordinary eye-splice turned around a large oblong- 

 thimble, the ends tucked three times, tapered, and trimmed the same as 

 though it were a hemp or mauila rope. We serve the splice occasion- 

 ally with annealed iron wire when we wish to make a particularly neat 

 job, but it is not at all necessary. 



The rope being galvanized requires uo preservation while new, but if 

 from long service the zinc should be worn off and the steel wires ex- 

 posed a coating of raw linseed oil will be of service. We have used no 

 preservative, and have had uo trouble from rusting. 



SAFETY HOOKS. 



The safety hooks (Plate XLV) are designed for the purpose of de- 

 taching the trawl or dredge when, from any cause, such as fonliug a 

 rock or burying in the soft ooze of the ocean bed, the tension on the 

 dredge rope exceeds the limit of safety. 



The rope is spliced into the eye c, the spiral spring is adjusted by 

 means of the nut on the end of the tension rod d, then placed in the 

 cylinder a and the cap b screwed on. The shoulders// on the hooks 

 will rest on the inner surface of the lower extremity of the cylinder 

 a. The trawl being shackled by passing the pin through the hooks, 

 and the necessary tension being put on it, the spring e will be com- 

 pressed, the shoulders // will extend below the end of the cylinder, 

 and the hooks will open, allowing the shackle pin to slip between them, 

 thus detaching the trawl and relieving the rope from undue strain. 

 The spring can be adjusted to release the trawl at any point between 

 3,000 and 6,000 pounds. 



THE DREDGING AND REELING ENGINES (PLATES XXIII, XXIV, and XXV). 



A detailed description of these engines is given in the engineer 

 department and need not be repeated. A brief mention of their de- 

 sign and construction may not, however, be out of place here. 



During the summer of 1881, while the plans for the Albatross were 

 being perfected, the writer examined every form of hoisting and reeling 

 engine within reach, as well as models in the Patent Office aud plans 

 of cngiues constructed by various builders, but found nothing fulfilling 

 our requirements. The type adopted on board the Fish Hawk, com- 

 bining the hoisting aud reeling eugine, using the same drum for hoist- 



