used for propelling the vessel, should be surveyed and be fitted the same way as the main boilers, and have a water and steam gauge, and all other fittings complete, and, as regards safety valves, should comply with the same regulations as the main boilers.

Launch Boilers.-109. The boilers of steam launches forming part of the statutory boat capacity of passenger steamers should, as regards construction, strength, material, safety valves, and other fittings, comply with the same regulations as the main boilers.

Stop Valves.-110. No boiler or steam chamber should be so constructed, fitted, or arranged that the escape of steam from it through the safety valves required by the Act of Parliament can be wholly, or partially, intercepted by the action of another valve.

A stop valve should always be fitted between the boiler and the steam pipe, and, where two or more boilers are connected with a steam receiver or superheater, between each boiler and the superheater or steam receiver. The necks of stop valves should be as short as practicable.

Water-gauges, Test Cocks, &c.-111. Each boiler should be fitted with a glass water-gauge, at least three test cocks, and a steam gauge. Boilers that are fired from both ends, and those of unusual width, should have a glass water-gauge and three test cocks at each end or side, as the case may be. When a steamer has more than one boiler, each boiler should be treated as a separate one, and have all the requisite fittings.

When the water-gauge cocks are not attached directly to the shell of the boiler, but to a standpipe or column, cocks should as a general rule be fitted between the boiler and the standpipes, &c. Such cocks need not, however, be insisted on in cases where the columns, standpipes, &c., are of moderate length and of suitable strength, provided that the diameter of the bore at any part is not less than 3 ins.

If the column, standpipes, &c., are of less diameter than 3 ins., and the pipes are bolted to the boiler without the intervention of cocks or valves, the arrangement need not be objected to, if otherwise satisfactory, providing there is no difficulty in keeping the passages at the ends clear, and ascertaining that they are so. To do this it will be necessary that the passage in the part of the column between the top and bottom gauge-glass cocks be cut off or closed, which may be done permanently, or by the interposition of a cock or valve at that part. The latter is a convenient and desirable arrangement even when cocks are fitted on the boiler.

In the case of high-pressure boilers, it is desirable that the cocks in connection with the water-gauges should be fitted with handles which can be expeditiously manipulated from a convenient position.

It is desirable in all cases that test cocks should be fitted directly to the skin of the boiler, and when the water-gauge is attached to a column, the opening through which is stopped or can be cut off, the test cocks must be fitted directly to the skin of the boiler.

The Surveyors should satisfy themselves by actual examination whether the glass water-gauges of the boilers of the vessels they survey are clear, and also whether they are fitted with automatic valves or fittings, as the existence of such fittings cannot always be ascertained by external examination. In all cases where automatic gauges

are fitted, full particulars thereof should be submitted for consideration and approval before the gauges are passed.

No new arrangement to be sanctioned until plans have been submitted to Board of Trade.-112. Surveyors are to be most careful not to give any official sanction to any new or unusual arrangement or construction of marine steam boilers, without first obtaining the permission of the Board, nor should they give any written approval of any invention, or arrangement, unless by direction of the Board of Trade; and whenever they know that any new arrangement of boiler or other apparatus is to be fitted to a vessel that is intended to have a passenger certificate, they should, as soon as possible, with a view to preventing subsequent delays and questions, obtain plans thereof and submit the same for the consideration of the Board of Trade.

When any deviation from an approved plan is made, full particulars thereof should be submitted for the Board's consideration, and when any deviation is sanctioned it is only for that particular case, unless otherwise stated.

Surveyors should in all cases record on their declarations whether the boilers are made of iron or steel, and if made partly of steel and partly of iron they should specify for what parts either metal is used.

Hydraulic Test.-115. Surveyors should see all new boilers, and boilers that have been taken out of the ship for a thorough repair, tested by hydraulic pressure to double the working pressure that will be allowed. The test should be made previous to the boilers being placed in the vessel, and before they are lagged.

The hydraulic test should not be witnessed by the Surveyors in any case where the Board's regulations as to strength, material, method of construction, treatment, &c., are not complied with, unless they have previously submitted the details of the particular case for the consideration of the Board and obtained authority to witness the test.

The hydraulic test should not be applied until the boiler has been examined in accordance with clause 113, and until the strength has been calculated from the necessary measurements taken from the boiler itself as per clause 114.

When the boilers are in the vessel the Surveyor may, at any time he thinks it necessary, before he gives a declaration, have them tested by hydraulic pressure to satisfy himself as to any doubtful part, or of places not easy of access, care being taken in the case of old boilers not to overstrain them; but the test must always exceed the working

pressure.

No test should be considered good in which the boiler has not borne satisfactorily the intended test pressure for at least ten consecutive minutes.

The amount of the hydraulic pressure test, and the date on which it was last applied to the boilers, should be inserted in the Surveyor's declaration, and recorded in the Office Boiler Book.

Examination and Testing of Steam Pipes.-116. Surveyors should pay particular attention to the examination and testing of steam pipes.

All new copper steam pipes should be tested by hydraulic pressure to not less than twice and not more than two and one-half times the working pressure. The higher test should be that usually employed. When, however, special considerations arise the case should be fully submitted and instructions obtained before the Surveyor proceeds with the hydraulic test.

Wrought-iron lap-welded steam pipes should be tested by hydraulic pressure when new to at least twice the working pressure, but not to more than three times, unless the case has been specially submitted to the Board for consideration.

As regards old pipes the Surveyor may at any time he thinks it necessary, before he gives a declaration, have them tested by hydraulic pressure to satisfy himself as to any doubtful part, but they should be tested, with the lagging removed for examination, at least once in about every four years, to not less than double the working pressure. A record of the test should be kept in the Office Boiler Book.

Draining Steam Pipes.-There should be efficient means provided for draining all steam pipes. Boiler stop-valves cannot be regarded as suitable for that purpose. All drain cocks or valves should be accessible and so placed as to render it practicable to drain the water from any portion of the steam pipes or chests in connection therewith. Drain pipes should be fitted to drain cocks or valves when the latter are in such a position that the water or steam discharged therefrom would be likely to cause personal injury. It is desirable that the drains should be automatic in their action.

Copper Pipes.-117. The working pressure of well-made copper pipes when the joints are brazed is found by the following formula:

When the pipes are solid drawn and not over 8 ins. diameter, substitute in the foregoing formula for

32

Wrought Iron Pipes.-118. The internal pressure on wrought-iron pipes made of good material, which are lap-welded and are a sound job, may be determined by the following formula, provided that the thickness is not less than in. :—

Feed Pipes. 119. Feed pipes should be made sufficient for a pressure 20% in excess of the boiler pressure.

Expansion Joints. 120. In all cases in which a socket expansion joint is fitted to a bent steam pipe, the Surveyor should require a fixed gland and bolts to be fitted, in order to prevent the end of the pipe being forced out of the socket. This regulation should be complied with in all cases of bent pipes fitted with socket expansion joints. It is also desirable that fixed glands and bolts should be fitted to the expansion joints of straight steam pipes, as cases have occurred, particularly with small straight pipes, in which the ends of the pipes have been forced out of the sockets.

Cast Iron in Boilers and Steam Pipes, Stand Pipes, Cocks, &c.121. In all boilers in which the Surveyors find that cast iron is employed in such a manner as to be subject to the pressure of steam or water, they are directed to report the circumstances to the Board of Trade. Cast-iron standpipes or cocks through which hot brine would have to pass should never be passed. Surveyors should also discourage the use of cast iron for chocks and saddles for boilers. Particular attention should be paid to the chocking of boilers, more especially when they are fired athwartships.

Pressure fixed by one Surveyor not to be increased by another.—122.

A pressure once allowed on the boiler of a passenger steam ship is not, under any circumstances whatever, to be increased unless the Surveyor has previously referred the matter to the Board. In cases where a Surveyor is of opinion that an increased pressure may with safety be allowed, he should communicate with the Surveyor who last surveyed the vessel; and if, on learning the reasons why the existing pressure was formerly allowed, the Surveyor is still of opinion that it may be increased, he should communicate all the facts of the case to the Board of Trade; but, as above stated, the pressure should not in any case be increased until the question has been decided by them.

SAFETY VALVES

Provisions as regards Safety Valves.-123. The Engineer-Surveyor shall declare, amongst other things, the limits of the weight to be placed on the safety valves; that the safety valves are such and in such condition as required by the Act, and that the machinery is sufficient for the service for the time he fixes, and is in good condition for that time.

The locked-up valves, i.e. those out of the control of the engineer when steam is up, should have an area not less, and a pressure not greater, than those which are not locked up, if any such valves are fitted.

Cases have come under the notice of the Board of Trade, in which steam ships have been surveyed, and passed by the Surveyors, with pipes between the boilers and the safety-valve chests. Such arrangement is not in accordance with the Act, which distinctly provides that the safety valves shall be upon the boilers.

The Surveyors are instructed that in all new boilers, and whenever alterations can be easily made, the valve chest should be placed directly on the boiler and the neck, or part between the chest and the flange

which is bolted on to the boiler, should be as short as possible and be cast in one with the chest.

The Surveyors should note that it is not intended by this instruction that vessels with old boilers which have been previously passed with such an arrangement should be detained for the alterations to be carried out.

Of course in any case in which a Surveyor is of opinion that it is positively dangerous to have a length of pipe between the boilers and the safety-valve chest, it is his duty at once to insist on the requisite alterations being made before granting a declaration.

If any person place an undue weight on the safety valve of any steam ship, or, in the case of steam ships surveyed under the Act, increase such weight beyond the limits fixed by the Engineer-Surveyor, he shall, in addition to any other liabilities he may incur by so doing, incur a penalty not exceeding one hundred pounds.

Area of Safety Valves.-124. The area per square foot of fire-grate surface of the locked-up safety valves should not be less than that given in the following tables opposite the boiler pressure intended, but in no case should the valves be less than two inches in diameter. This applies to new vessels or vessels which have not received a passenger certificate.

When, however, the valves are of the common description, and are made in accordance with the tables, it will be necessary to fit them with springs having great elasticity, or to provide other means to keep the accumulation within moderate limits; and as boilers with forced draught may require valves considerably larger than those found by the tables, the design of the valves proposed for such boilers, together with the estimated coal consumption per square foot of firegrate, should be submitted to the Board for consideration.

When ascertaining the fire-grate area, the length of the grate should be measured from the inner edge of the dead plate to the front of the bridge, and the width from side to side of the furnace on the top of the bars at the middle of their length.

In the case of vessels that have not had a passenger certificate, if there is only one safety valve on any boiler, the Surveyor should not grant a declaration without first referring the case to the Board for special instructions.