Philosophical transactions, Vol. L. Part I. For the year 1757.: Giving some account of the present undertakings, studies, and labours, of the ingenious, in many considerable parts of the world.Various
History
Philosophical transactions, Vol. L. Part I. For the year 1757.: Giving some account of the present undertakings, studies, and labours, of the ingenious, in many considerable parts of the world.
Various
Science -- Periodicals
THE Royal William, a first rate man of war, built about 40 years ago,
having, upon examination, been judged in so good a state, as to be
worthy of repairing for sea service, was ordered into dock, and brought
thither on the 29th of June 1756. On these occasions it is usual to lay
across the middle line of the bottom of the dock, at distances of about
five feet from one another, thick pieces of oak timber of about four
feet long; their upper surfaces lying in the same plane, or so posited,
that a line stretched from the two extreme blocks will touch all the
intermediate ones; and on the middle of these blocks the keel of the
ship is to rest. On the said day the tide did not rise so high as was
expected; and there was not quite depth enough of water to float the
ship in, and set her on the blocks, notwithstanding the assistance of
an empty lighter, which, being fixed to the stern, lifted the ship at
the end six inches: and as the officers knew they should not have so
much water again before the next spring-tides, they were determined to
heave her in; which is a very common operation in most dock-yards. Now
it so happened, thro’ the great weight of the head and stern, that the
ship cambered very much; that is, her keel, from being straight, was
become much curved, the two extremities hanging lower than the middle
part by many inches; and consequently the foremost part of the keel,
instead of sliding over the blocks, forced all the foremost ones away,
for above 60 feet; whereby that part of the keel rested on the bottom
or floor of the dock, and the aftermost part rested on such of the
blocks, as had escaped the violence, which had displaced the others.
In this situation the keel was very far from being strait; and so it
was resolved to lift by main force the head of the ship, until the keel
should be strait; and in that position to support it by the blocks,
which had been forced away from their places.
For this purpose there were set up, under the wales and other parts of
the ship, to the length of near 80 feet of the stem, as many shoars,
as were judged necessary; and also nine pair of bed-screws, three pair
under each bow, and three pair under the knee of the head. At each
shoar a workman was appointed, to drive wedges between the heels of
the shoars and the parts of the dock whereon they rested; whereby the
shoars were raised end-wise, and consequently the body of the ship
lifted at the same time. While this was doing, the 18 screws were also
at work: and between these efforts the fore part of the ship was raised
upwards of 19 inches, so much being necessary to bring the fore part of
the keel in a right line with the hinder part.
In this service were employed about 270 men; whereof about 144 worked
at the screws, and the others worked at the shoars with their mawls and
wedges; and the whole operation was performed in about seven hours.
Public-domain text, read in full here on John Shaqi.
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