The following is taken from George Strong Nares' "Seamanship" (2nd edition, 1862)
CLIFFORD'S METHOD OF LOWERING BOATS.
Fig. 1 shows a side view of a boat, and the gear used for lowering. A is a roller which works freely in bearings, at each side of the boat, under one of the seats. B is the lowering rope, which is slackened off when lowering. One end is made fast to the roller, and is then wound on it a length equal to the distance the boat will have to descend from the davits to the water. C C are two other single ropes or pendants, which are made fast to the davits and pass through the three sheave blocks D D: then through the leading blocks F F; the ends of each then enter the same hole in the roller, but in opposite directions. By hauling on the lowering B the roller is turned round, and the pendants are wound on it a length equal to the distance the boat will have to descend to the water. The blocks D D act like a sailor's "turn and a half" in the boat, on each pendant, breaking the strain to the man lowering, and giving him control over the descent of the boat, whatever its weight may be. The nip of the block only exists so long as there is any strain on the pendants passing through it, and ceases on the lowering line being let go when the boat reaches the water. This power of the block to decrease and control the descending weight of the boat whilst the lowering rope is in the hand of the man attending to it, and yet allowing all to run free the moment it is let go, is its chief feature, and that which befits it for the purpose to which it is here applied, and for which it was specially designed. The pendants, being tapered at the ends, freely overhaul themselves.
Fig. 2 is a cross-view of a boat hanging to the ship's side, lashed and ready for lowering. E E are the steadying lines attached to the sides of the boat; the nip in the rope in the block, D D, drags the block in a direction contrary to the descent of the boat, tightens the steadying lines, and thus prevents the boat from canting. Consequently the greater the weight of the boat, the greater the security against canting. The gripe G is made in two parts, with thimbles at each end, held together by a lanyard. When the boat is hanging on the pendants, the gripes are passed round the boat, and the thimbles H H up the prongs I I; the lanyard K is then hauled taut, and thus the boat is lashed to the ship's side. When the boat is lowered, the thimbles slip down the prongs, and the boat is free.
|DESCRIPTION OP THE PLATES.|
|A||Roller on which pendants are wound.||F||Single block on keel, taking the weight of the boat.|
|B||Lowering line, which is slacked off when lowering.||G||Boat's gripes in two parts.|
|C||Pendants.||H||Thimbles, at each end of gripes, which pass down prongs.|
|D||Three sheave block, the nip giving controlling power.||I||Prongs down which the thimbles pass as boat is lowered.|
|E||Steadying lines, to prevent the boat from canting.||K||Lanyard for setting up gripes.|
DIRECTIONS FOR LOWERING.
One of the boat's crew must take charge of the lowering line B, throw the spare line over the boat's side, and then with one round turn on the cleat slacken it off slowly. The gripes will release themselves by the thimbles passing down the prongs. When the boat reaches the water, let go the rope, the pendants not being fastened will overhaul, and the boat will be perfectly free.