following table. When special steel is used, the sizes are to be submitted for consideration.

1. For petrol or paraffin engines for smooth-water services :

In engines of two-stroke cycle, n is to be taken as twice the number of cylinders.

2. When ordinary deep thrust collars are used, the diameter of the shaft between the collars is to be at least ths of that of the intermediate shaft.

3. The above rules apply only to engines in which the initial pressure does not exceed 250 lbs. per sq. in. In the cases of semi-Diesel and other engines in which higher initial pressures are employed, particulars should be submitted for special consideration.

FUEL TANKS AND CONNECTIONS.

Section 4.-1. Separate fuel tanks are to be tested with all fittings, to a head of at least 15 ft. of water. If pressure feed tanks are employed, they are to be tested to twice the working pressure which will come on them, but at least to a head of 15 ft. of water. If the tanks are made of iron or steel they should be galvanised.

2. Strong and readily removable metallic gauze diaphragms should be fitted at all openings on petrol tanks.

3. Paraffin or heavy oil tanks, not used under pressure, are to be fitted with air pipes leading above deck. Pressure-feed tanks and tanks containing petrol, should be provided with escape valves discharging into pipes leading to the atmosphere above deck. The upper ends of all air pipes are to be turned down, and pipes above 1 in. diameter are to be provided with gauze diaphragms at the end.

4. No glass gauges are to be fitted to fuel tanks containing either petrol, paraffin, or heavy oil.

5. Filling pipes are to be carried through the deck so that the gas displaced from the tanks has free escape to the atmosphere.

6. Separate fuel tanks should be provided with metal-lined trays to prevent any possible leakage from them flowing into the bilges, or saturating woodwork. Arrangements are to be provided for emptying the tanks and draining the trays beneath them. For petrol tanks the trays must have drains leading overboard where possible, or they should be gauze-covered trays with means for draining them.

7. All fuel pipes are to be annealed seamless copper with flexible bends. Their joints are to be conical, metal to metal. A cock or valve is to be fitted at each end of the pipe conveying the fuel from the tank to the carburettor or vaporiser. The fuel pipes should be led in positions where they are protected from mechanical injury, and can be exposed to view throughout their whole length.

8. The engine-room, and the compartment in which the fuel tanks are situated, are to be efficiently ventilated.

9. An approved fire-extinguishing apparatus must be supplied.

PERIODICAL SURVEYS.

Section 5.-1. The machinery is to be submitted to survey annually. At these surveys the cylinders, pistons, connecting-rods,

crank and other shafts, inlet and exhaust valves and gear, clutches, reversing gear, propeller, sea connections, and pumps, are to be examined. The electric ignition is to be examined and the electric leads tested. The fuel tanks and all connections are to be examined, and if deemed necessary by the surveyor, to be tested to the same pressure as required when new. If practicable, the engines should be tested under working conditions.

2. The screw shaft is to be drawn at intervals of not more than two years.

SECTION B.-NESTED BOATS

General Description.-By the terms of General Rule 12 of the Life-saving Appliances Rules (1914), additional lifeboats may be stowed in tiers of two or three one above another, or they may, subject to such conditions as the Board of Trade may impose, be fitted one within another.

Captain P. D. Murray, of Liverpool, has had an extensive experience with the Mercantile Marine Service, having served in sailing and steam vessels for 21 years at sea, and was marine superintendent of two Atlantic steamship companies for another 21 years.

The sinking of the R.M.S. Titanic, as the result of a collision with an iceberg, prompted Captain Murray to endeavour to construct ordinary open lifeboats of Class I. of sufficient strength so as to "nest one or more boats within another, and thus provide accommodation for all persons on board the largest passenger vessels, which would include the crew in addition to the full number of passengers.

These particular boats designed by Captain Murray form the subject of the present section.

For classification purposes they are treated as Class IA open lifeboats, but they differ from the ordinary lifeboats in that the thwarts are movable, not portable, and made to hinge to one side.

The boats are constructed of wood of the best materials and workmanship.

Fig. 149 shows the general stowage of three of these patent boats in a nest.

For the purpose of nesting, the thwarts of the two lower boats are hinged to the side of the boat, and to secure the necessary strength for sustaining the upper boat, a fore and aft stringer is

fitted around the inside of the boat on a line with the thwarts, strengthened by galvanised steel angle bars secured through the fore and aft stringer, planking, stem, and sternpost. By fitting three or more deep frames connecting from the deep keelson and extending to the fore and aft stringers, the boat is well tied together both in a longitudinal and in a transverse direction. These web frames are strengthened by angle bars fitted in one piece, following the line of the upper edge of deep frames across the keelson, and secured to the fore and aft angles and keelson.

A deep keelson is fitted in one continuous length, made from pitch pine and forms a good stiff backbone to support the weight

FIG. 149. Section showing stowage of Captain Murray's nested lifeboats.

of the upper boat. A recess is provided for the keel of the upper boat to rest on the keelson, by forming fore and aft seats, resting on the deep frames, and extending the full length on both sides of the boat. Two additional fore and aft seats are fitted above the lower ones so that seating accommodation below the thwarts is provided for about half the number the boat is certified to carry, which ensures greater stability, and freedom for the rowers at the thwarts.

The side stringers and thwarts provide seating accommodation for the remainder of the persons carried.

The space between the fore and aft stringers and the lower edge of the side seats, around the sides of the boat, provide ample space for the required volume of buoyancy air-cases, viz.: one

cubic foot for every ten cubic feet of boat capacity obtained by Stirling's Rule.

The air-cases are of special design, giving the greatest buoyancy at the bilge of the boat.

Under the seats on each side of the keelson is provided stowage for water and biscuit tanks, and in a locker fitted aft are placed the liquid compass, distress signals, etc.

The space between the seats in the bottom of the boat provide stowage for oars, mast, sails, and full equipment.

Four hinged thwarts are provided for oarsmen, double banked, and supplied with special fittings to permit of stowing the thwarts on edge on top of the fore and aft stringer, when the boats are nested.

The general arrangement of a nest of lifeboats is shown in Fig. 151, which indicates the positions of the thwarts.

As the upper boat is launched, the thwarts are placed across the second boat and secured on opposite sides by cleats, ready for