The Seventh Improvement

Consists in making the upper deck of a vessel in two thicknesses of plank instead of only one thickness, and in fastening such deck with my hereinafter described clip bolts.

In a vessel of 200 tons burthen, the under thickness of the deck should be one inch, and the upper thickness should be two inches -- and as the chief object of the two thicknesses is to create a stop to the caulking, the under plank, which is slightly nailed to the beams, need not be so narrow as is usual for the plank of the upper decks.

In order not to diminish the thickness of waterways in the parts where the scupper holes will be fixed, the waterways are not to be in two thicknesses, but there is to be a rabbet on the inner edge, leaving only an inch thickness on a small part of the under side of the rabbet, so as to be flush with the under thickness of the deck, and thus create a stop for the caulking at the waterway seam.

The under planks may be placed upon the beams diagonally, but I prefer the under plank to be placed longitudinally, because greater lengths can be worked, and the longer the lengths of the plank, the fewer will be the butts, and the greater the strength. The clip bolts for the deck of the above sized vessel should be three eigths of an inch diameter, and seven and a half inches long.

Having many years ago caused several vessels to be built with the deck in two thicknesses and fastened with jagged bolts, I make no claim for that improvement, or for the defined dimensions -- but what I do claim is, the combination of the two thicknesses of deck, with their fastening by my hereinafter described clip bolts. [page 52]

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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Copyright © 1996 Lars Bruzelius