ordinary round bar davits and turning them outboard against a vessel's list.

It is false economy to nip down the overhang of the davit to the lowest limits in order to save weight of material and cheaper production. When the boat is launched overboard there must be at least 12 inches clearance at the light water-line, between

the boat and the ship's side, the vessel being in an upright position. The height of the head of the davit above the upper support of the boat deck, should be such that when the lifeboat is stowed in the chocks, there will be a distance of at least three blocks between the lower and upper fall blocks. This distance should allow the boat to be raised clear of the chocks, in case it becomes impossible to hinge the latter down.

Particular attention must be given to the method of securing the collars and heel sockets, sufficient riveting being arranged to maintain an efficient connection to the hull of the vessel, especially in view of the stress exerted on the davit when the vessel is rolling heavily in a seaway.

TABLE XXX.

APPROXIMATE WEIGHT AND STRENGTH OF STANDARD QUALITY MANILA ROPE.*

The weight and strength of manila rope per table, is approximate and may vary slightly either way. Manila and sisal standard rope will weigh about alike. In the lower grades of manila and sisal there are greater variations in weight and strength, according to quality. Four (4) strand rope weighs from 5 per cent. to 7 per cent. heavier than three (3) strand plain laid rope. Manila rope runs approximately 25 per cent. stronger than sisal.

* Supplied by the Waterbury Company, New York.

The emergency lifeboats are carried outboard and near the bridge, during the whole of the voyage at sea, and maintained in a position of security by fitting pudding fenders attached to the davits (See Figs. 238 and 240), the boat being hauled close in to the fenders by canvas griping bands. Ordinary rope lashings are not recommended in place of the griping bands, as the continual rolling of the ship produces too much friction between the rope and boat planking, with detrimental effect to the latter.

In arranging the size and pattern of blocks, due regard should be paid to the standard of strength, or factor of safety, recognised by the Board of Trade in connection with details of davit equipment.

It is anticipated that regulations will soon be in operation whereby detailed information will become available for the use of the shipbuilder to fix the sizes of the blocks and associated fittings.

The writer has often heard complaints from ships' officers as to the unreliability of tarred hemp for davit falls. The action of the weather is often responsible for the sudden collapse of the falls without giving previous warning or any visible indication of weakness.

The working load of manila rope is usually about one-fifth of the breaking stress. All blocks should be fitted with patent roller sheaves. Manila is stronger than tarred hemp. Ordinary hemp rope, unless it is tarred, quickly deteriorates when exposed to the weather; the effect of tarring, however, reduces its strength.

Manila hemp is obtained from a species of wild plantain belonging to the banana family, and grows in the Philippine Islands. The fibre is silky and lustrous in appearance and very tenacious, but light in weight. The strength and weight of manila rope is shown in Table XXX.

The usual practice is to fit wooden blocks when serving manila falls, and iron blocks for wire rope. General experience has proved it an advantage to have iron non-toppling blocks instead of blocks made of wood, for the weight of the former assists the block in preventing it from turning over when recovering the falls.

Special patent roller sheaves are very necessary, and it is an added advantage to bush the sheave pins to prevent friction.

The becket is secured to the breech-end of the block, the purpose of which is to link up with the shackle and thimble attached to the standing part of the tackle. When the upper

block is fitted with treble sheaves, and the lower block with double sheaves, then the becket is fitted on the lower block, but when the upper and lower blocks are fitted with the same number of sheaves, then the becket is fitted on the upper block.

TABLE XXXI.

FIBRE-CLAD WIRE HOISTING ROPE, CRUCIBLE CAST STEEL.

Before reeving the falls they should be carefully stretched; and after reeving, the shackle attached to the becket should be disconnected and the turns taken out of the falls before replacing.

The Board of Trade have issued instructions to the effect, that in order to provide for speedily detaching the falls by hand when the boat is waterborne, all lower fall blocks are to be fitted with a suitable ring or long link for attachment to the sling hooks fitted in the boat, unless some approved form of disengaging gear is adopted. The eye on the block and the ring or link are to be such as to provide a factor of safety of at least four, with a dead working load equivalent to the total weight of boát, equipment, and full complement of persons.

The following extract has been supplied by the Waterbury Company of New York, Chicago, etc.

Notes on Use and Care of Rope.

Deterioration in rope is both mechanical and chemical: first, due to surface wear or from friction between fibres; secondly, from exposure to weather and acids. Surface wear on ropes likewise follows where worked through blocks or where sheave holes are too small for easy clearance or where blocks become fouled, causing improper alignment, the result of which is chafing of the rope.

Ropes swell to some extent after being wet. Blocks with large enough sheave grooves should be used to take care of swell. Unlike metal and other similar substances, fibre rope has not a permanent elastic limit in which it may be worked indefinitely without injury. Owing to the tendency of the fibres to slip one upon another, the rope gradually loses its cohesion under the repetition of very moderate tension, and may be seriously weakened by constantly working. If fibre rope is subjected to a sudden stress or even to a stress approaching that of breaking, its strength is permanently reduced, and it may be expected to give way under a very moderate pull. Hence it is advisable to allow for liberal factors of safety, both as to working and breaking strains.

Internal friction between the fibres increases to some extent when the rope is worked over a sheave. This ultimately has a tendency to break up the fibres, which also suffer a loss of vitality through heat caused by friction. The smaller the diameter of sheave in this connection the greater the friction. The use of sheaves of the largest diameter permissible is advisable, likewise rope, as the ultimate results will justify.

All rope should be kept clean and free from sand, mud, or other matter containing grit. Chemical deterioration from rotting, or termed by some "dry rot," generally increases through rope becoming water-logged and not given an opportunity to dry out in the open air. Allow the rope to dry naturally. Do not cover or prevent drainage as it retards the drying out process.

When dragging rope over the ground it weakens the rope, and dirt and grit are picked up which grind in when the rope is used again. Unnecessary surface wear often occurs with hoisting machinery by contact against iron beams or the edges of pulley blocks. In transmission the surface friction rope against the sheave also wears it, but the wear is inappreciable as compared with that of a poor installation.

Be careful in storing your rope to prevent contact with