IMPROVED CAPSTAN AND WINDLASS. j gy 



which the model 1 have had the honour of laying before the the method 

 Society represents, none of the lateral friction of the messen- ""^^ proposed. 

 ger or cable against the whelps of the capstan, (which all 

 the other methods of eiiecting the same purpose before men- 

 tioned labour under,) can possibly take place, and of course 

 the wear of the me^senger occasioned thereby will be entirely 

 avoided in it, while it performs its purport- more smoothly, 

 equally, and with a less moving power than any of them. 



My method of preventing the necessity of surging con- -j-j^j^ j^g^^jj^jed* 

 sists in the simple addition of a second smaller ba'-rei or cap- 

 stan of less dimensions to the large one; beside which it is to 

 be placed in a similar manner, and which need not in general 

 exceed the size of a half-barrel cask. The coils of ihe mes- 

 senger are to be passed alternately round the large capstan 

 and this small barrel, but with their direction reversed on the 

 different barrels, so that they may cross each other in the in- 

 terval between the barrels, in order that they may have the 

 more extensive contact with, and better gripe ou each barrel. 

 To keep the coils distinct, and prevent their touching each 

 other in passing from one barrel to the other, projecting 

 rings are fastened round each barrel, at a distance from each 

 other equal to about two diameters of the messenger and the 

 thickness of the ring. These rings should be so fixed on the 

 two barrels, that those on one barrel should be exactly op- 

 posite the middle of the intervals between those on the other 

 barrel: and this is the only circumstance, which requires 

 any particular attention in the construction of this capstan. 

 The rings should project about as much as the cable or mes- 

 senger from the barrels, which may be formed with whelps, 

 and in every other respect, not before mentioned, in the 

 usual manner for capstjin barrels, only that I would recom- 

 mend the whelps to be formed without any inclinatior. in- 

 wards at the top, but to stand upright all round, ho as to form 

 the body of the capstan in the shape of a polygonal Drism, if 

 the intervals between the whelps are filled up, in order that 

 the coils may have equal tension at the top and at the bot- 

 tom of the barrels, and that the defect which conical barrels 

 cause in this respect may be avoided. 



The small barrel should be furnished with falling palis as 

 well as the large cue; a fixed iron spindle ascending froiTi 

 • the 



