Crab

A sort of little capstan, formed of a kind of wooden pillar, whose lower end works in a socket whilst the middle traverses or turns round in partners which clip it in a circle. In its upper end are two holes to receive bars, which act as leavers, and by which it is turned round and serves as a capstan for raising of weights, etc. By a machine of this kind, so simple in its construction, may be hove up the frame timbers, etc., of vessels when building. For this purpose it is placed between two floor timbers, while the partners which clip it in the middle may be of four or five-inch plank fastened on the same floors. A block is fastened beneath in the slip, with a central hole for its lower end to work in. Besides the crab here described there is another sort which is shorter and portable. The latter is fitted in a frame composed of cheeks, across which are the partners, and at the bottom a little platform to receive the spindle.