ACCUMULATORS 275 



Two other pieces of gear are advisable — an accumu- 

 lator and a recording sheave. The old type of accumu- 

 lator consisted of a number of stout cylindrical rubber 

 straps between two boards, the whole slung from a 

 derrick or spar, and carrying the block over which the 

 trawl rope runs out-board ; the object of this was to 

 lessen any sudden strain on the rope due to the trawl 

 hitching, and to warn the man in charge of such strain. 

 Since the invention of pneumatic tyres, it has been so 

 difficult to get reasonably pure rubber that the less 

 bulky and more reliable steel spring accumulators 

 seem to be advisable. If trawling from a derrick, the 

 topping lift, passing over a block stropped to the mast, 

 is brought down and made fast to the head of a long 

 steel spring, rigged up against the mast.* A sudden 

 strain on the rope pulls down the derrick head, the 

 spring yielding. Such an indication will often enable 

 the gear to be recovered before it is seriously damaged, 

 while with very severe pitches the warp is (probably) 

 saved from snapping. 



For really heavy trawling a nipper may be substi- 

 tuted for the accumulator, or used in conjunction with it. 

 This (Fig. 195) is attached by means of a hemp rope to the 

 winch or some other solid deck fixture, and the slack 

 tripping line is also shackled to the same support ; the 

 accompanying figure will explain the method em- 

 ployed. Any undue strain causes the hemp rope to 

 break, allowing the wire to pay out from the drum or 

 reel (if the brake is left open), while the nipper is 

 checked by the tripping line, and either falls to the 

 deck or allows the wire to render through it, according 

 to the particular make fitted. A small nipper will also 



* This arrangement is figured in Report of the Siboga 

 Expedition, " Description of the Ship," by Lieutenant G. F. 

 Tydeman, Plate I. 



