365 
the Necessity of lifting Ships* 
ter the vessel was in, and the water gone, they were all 
found to have kept their situations, as placed before the 
ship rested upon them. Shores in their wake were then 
erected to sustain the ship, prior to the said blocks being 
taken from under the keel. The process of clearing them 
was, by applying the power of battering-rams to the 
sides of the outer ends of the horizontal wedges ; alter- 
nate blows being given fore and aft ; by which means 
they immediately receded, and the vertical wedges were 
disengaged. It was observed, even in this small ship, 
that the block which was formed of horizontal wedges 
of nine degrees, came away much easier than those of 
seven, and the one of seven than that of five. In remov- 
ing the aforesaid blocks by the power of the battering- 
rams, which were suspended in the hands of the men 
employed, by their holding ropes passed through holes 
for that purpose, it was remarked by Mr. Seppings, that 
the operation was laborious to the people ; they having 
to support the weight of the battering-rams, as well as to 
set them in motion. He then conceived an idea of affix- 
ing wheels near the extremity of that part of the rams 
which strikes the wedges. This was done before the 
blocks were again placed ; and it has since been found 
fully to answer the purpose intended, particularly in re- 
turning the horizontal wedges to their original situations, 
when the work is performed for which they were dis- 
placed ; the wheels also giving a great increase of power 
to the rams, and decrease of labour to the artificers ; be 
sides which, the blows are given with much more exact- 
ness. The same blocks were again laid in another dock, 
in which a two- decked ship of the line was docked. On 
examination they were found to be very severely pressed, 
but were removed with great ease. They were again 
placed in another dock in which a three- decked ship of 
the line was docked. This ship having in her foremast 
