The Twelfth Improvement

Consists in preventing the pins of ships' blocks from splitting the shell and from falling or working out of the pin-holes while in use on shipboard -- which I do by counter-sinking the pin-holes in the outer surfaces of the iron strap, or of the wood shell, if there be no iron strap, and by introducing into the pin holes a pin of such a peculiar form as, with the assistance of molten lead or other soft metal, secures the pin to the block, until the lead is cut out with a spike-nail, or a chisel, or other instrument. This pin, which fits rather slackly into the pin-hole, has, nearly close to each end, a groove turned in it all round, about a quarter of an inch wide, and about an eighth of an inch deep -- or instead of a groove, a shoulder or a notch may be cut into two parts of the pin, nearly close to its end.

Shipwreck and Collisions at Sea greatly prevented by Christophers' Patent Improvements in Naval Archtecture. With four plates.
London: J. Olliver, 59, Pall Mall; P. Richardson, 23, Cornhill. Liverpool: Deighton & Laughton. M.DCCC.L. 8vo, (4), 112 p, 4 pl.

Transcribed by Lars Bruzelius

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