I^BCESSITY OF LIFTING SHIPS. 185- 



(though many perfons before would not admit of, and otliers 

 could not underftand, the principle) that the facility of re- 

 moving the blocks or wedges, was proportionate to* the. 

 quantity of preflfure upon them. The block of five degrees and therefore 

 kept its place, but was immediately cleared, by applying the ^j^^ proper angfe' 

 power of the battering-rams to the fides of the outer ends of they would be ^ 



the horizontal wedges. The above experiments being com- J^^y^^'^apabie of 

 municated to the Navy Board, Mr. Seppings was di resiled to being driven out, 

 attend them, and explain the principle of his invention ; 

 which explanation, farther corroborated by the teftimonials of 

 his then Superior officers, was fo fatisfa^ory, that a dock was 

 ordered to be fitted at Plymouth under his immediate direc- 

 tions. The horizontal wedges in this, and in the other docks. The beftanglej* 

 that were aftetiwards fitted by him, are of caft iron, with a" for "aft iron^*^^^ 

 angle of about five degrees and a half, which, from repealed wedges. 

 trials, are found equal to any prefiure, having in no inftance 

 receded, and, when required, were eafily removed. The 

 vertical wedge is of wood, lined with a plate of wrought 

 iron, half an inch thick. On the bottom of the dock, in 

 the wake of each block, is a plate of iron three quarters of 

 an inch thick, fo that iron at all times a6ls in contad with- 

 ixon. 



The placing the fufiainin^ (hores, the form and fizes of the 

 wedges, and battering-rams, &c. alfo the procefs of taking 

 away, and again re-placing, the wedges of which the block 

 is compofed, are alfo exeusplified by a model. 



The dock being prepared at Plymouth, in Augnfi, 1801; A large 80- gua 



the Canopus, a large French SQ-^-nn fliip, was taken in, and f^'P *"^P^"1'^'^, 

 n 1 , L> , . ,A r r <• , by this method. 



retted upon the blocks ; and ttwcom})ie!e luccels ot the ex- 

 periment was fuch, that other docks were ordered to be 

 fitted at Sheernefs and Portfmouth dock-yards, under Mr. 

 Seppings's dire^^ions. Ai the former place a frigate, and at 

 the latter a three-decked (hip, were fufpended in like manner. 

 This happened in December, 1802, and January, 1803; and 

 the reports were fo favourable, as to cauie diredions to be 

 given for the general adoption of thefe blocks in his Majefty's 

 yards. This invention being thought of national confequence, 

 with refpecl to (liips, but particularly thofe of the navy, 

 government has been pleated to notice and reward Mr. Sep- 

 pings for it. 

 ' The time required to difengage each block, Is from one to -Each block may 



three minutes after the ftiores are placed : and a firft-rate fits.^^ difengaged in 



three minutes. 



on 



