Chap. XIII.

RAISING VESSELS, ETC.

1055

also a power should be applied that should overcome the suction, as well as the mass ofmud with which it was filled : to effect this, a power equal to 3^ millions of poundswas required. Two methods were adopted, each of which was sufficient for the end pro-posed, and the vessel would have been raised by the first, if a violent storm at the moment*it was lifted had not disengaged and deranged the apparatus, and allowed it again tosink : that first employed consisted of forming below a large and strong platform, witheighteen pieces of timber, nearly 100 feet in length, bound together with five rows of othertimbers laid in a transverse direction ; this frame was attached to the sunken vessel bycables passed through its port-holes : four vessels were placed under the frame by fillingthem with water, and when they were secured to it, a ship of the line was disposed at itsside, and five smaller vessels near the prow. On the first were ten capstans, whichworked a running tackle made fast to the sunken ship, and on the other five were placedseventeen other capstans, which worked a tackle attached to the head; they emptied thefour vessels filled with water, and at the same time turned all the capstans together, andby this process raised the vessel, which, as has been observed, again sunk : in the secondattempt they made use of the capstans as before, but instead of the submerged vessel, theyemployed sixty other capstans arranged upon a platform, placed over another seventy-four,two smaller ships, and two enormous levers.

The seventy-four gun-ship which was employed had three strong shears or derricksmounted on the deck, secured to the masts, and partly by arrangements made in the holdbelow ; besides these were eighteen others of a similar kind, but smaller in dimensions,which rested on the upper deck, and provided with as many windlasses: a piatform wasthrown out on the opposite side to that where the submerged vessel was level, with thedeck, and at the ends of the timbers, which projected as much as two-thirds the breadth ofthe seventy-four gun-ship, were suspended casks and boats loaded with stone, for thepurpose of keeping the works steady, when the whole of the thirty capstans, which weremounted on the platform and deck in three rows, were at full work ; the three sets of greatand the eighteen lesser derricks served as the points of suspension to the tackle, which thethirty capstans and eighteen windlasses worked.

Another apparatus of a similar kind was arranged upon a platform built over twolesser vessels on the other side of the submerged ship, and, to render the whole suffi-ciently buoyant, a number of large casks was attached in a circle : smaller platformswere established at the head, and another at the stern, each of which carried an enormouspiece of timber, slung in a manner to act as a powerful lever ; another served to moor apart of these preparations, and rows of piles, wherever they could be driven, were made useof; after every precaution had been taken to render the arrangements steady, 600 menat one time applied their strength to the capstans and windlasses, and raised the Phoenix bydegrees; when it had been raised 15 feet, they moved the whole of the works, togetherwith the sunken ship, along the canal, and commenced its demolition : in preparing theworks, and accomplishing this mighty task, upwards of two years was consumed, besides anenormous quantity of timber, iron, cordage, and labour.

In France , they have adopted several methods to raise vessels which have foundered orsunk in situations where it was necessary for the purposes of the navigation that theyshould be removed.

A vessel sunk at the mouth of the Loire was raised by Bonvaux after it had been in itsposition twenty-four years: his method consisted in passing four cables, by means of aniron bar, under it; the bars being formed in a manner to suit the curve of the ship’s side,which he had ascertained as well as he could; this curved iron bar was pointed at one end,and provided with an eye at the other, through which the cables might be passed anddrawn under the keel. This bar, formed on an arc of a circle, resembled, when mounted,a part of the felly of a wheel sustained by four of its spokes, whose central termination wasthreaded by a stout bolt, which answered the purpose of the nave or axle round which thewheel turned. The bolt passed into a vertical piece of timber, fixed at the lower end bymeans of an iron fork in the ship’s hull, and at the upper into some stout framing securedto some strong piles, driven for the purpose.

When the point of the bar was introduced and partly driven into the ground, the firstspoke or radius of the wheel was released by removing a screw, and when the bar ex-hibited its point on the other side, and it was sufficiently driven or forced through, theyemployed a three-toothed fork, the prongs of which entered into holes previously preparedin the iron bar, and then by main force pulled it through ; a running tackle was thenapplied, worked by a capstan placed on the deck of a small vessel moored near for thepurpose.

After four cables had been passed under the sunken ship, two barges were moored overthe hull of that bedded in the mud, on which four stout timbers or masts were laid; to thesewere attached the ropes, firmly secured ; when the tide rose the whole became buoyant,and four or five tides enabled the sunken vessel to be towed on shore, where it was left atlow water, to be demolished or broken up.