The principal object of this invention is, to provide a cheap substitute for dry docks, where it has not been thought expedient or practicable to construct them; and, both in point of economy and dispatch, it has been found completely to answer the purpose for which it was originally intended.
The patent slip, after the extensive experience that has now been had of it, is admitted to posses the following advantages:--
1. A durable and substantial slip may be constructed, under favourable circumstances, at about one-tenth of the expense of a fry dock, and be laid down in situations where it is almost impossible, from the nature of the ground, or the want of a rise and fall of tide, to have a dock built.
2. The whole apparatus can be removed from one place to another, and be carried on shipboard.
3. Where a sufficient length of slip can be obtained, a number of vessels may be upon it at once; and, in point of fact, two or more are often upon the slips already constructed, and under repair, at the same time.
4. Among the other advantages peculiar to the slip, it may be observed, that, every part of the vessel being above ground, the air has a free circulation to her bottom and all around her; in executing the repairs, the men work with much more comfort, and of course more expeditiously; and, in winter especially, they have better and longer light than within the walls of a dry dock; while considerable time is saved in the carriage of the necessary materials. The vessel, in short, is in a similar situation to one upon a building slip.
5. No previous preparation of bilge-ways is necessary, as the vessel is blocked upon her keel, the same as if in a dock; and she is exposed to no strain whatever, the mechanical power being solely attached to the carriage which supports her, and upon which she is hauled up.
6. A ship may be hauled up, have her bottom inspected, and even get a trifling repair, and be launched the same tide; and the process of repairing one vessel is never interrupted by the hauling up of another, -- an interruption which takes place in docks, from the necessity of letting in the water when another vessel is to be admitted.
7. A vessel is hauled up at the rate of 2½ to 5 feet per minute, by six men to every 100 tons; so that the expense both of taking up and launching one of from 300 to 500 tons, does not exceed forty shillings.
In addition to the above explanations, see Plate X. which exhibits all the principal pieces of timber, and the method of binding and fastening them together in their respective places.
Transcribed by Lars Bruzelius
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Copyright © 1997 Lars Bruzelius.