THE recent notices in the press, both written and pictorial, of the latest production of the ROYAL NATIONAL LIFEBOAT INSTITUTION—" the first steam Lifeboat "—have been so full, that we can quite imagine some of the Society's friends and supporters, on opening the present number of the journal, and seeing the heading of this article, exclaiming, " What, again! C'est vraiment trop fort! " but we hope those inclined to do so •will forgive us for once more dwelling on the subject, on account of the important bearing it has on the mison d'etre of this Institution, namely " Saving Life from Shipwreck;" also, if we may so say, the evidence it gives that the Institution is not resting on its laurels, bnt is still quite alive to the necessity for keeping pace with the times, by taking advantage of every advancement of scientific research, combined with the results of practical experience that bear on its work.

Indeed, we may in the present case almost claim that it has gone farther than that, and by building this boat has embarked on the often dangerous and alwajs costly undertaking of proving the value of new ideas. The outcome of the previous steps taken by the Institution to promote the production of a really serviceable steam Life-boat were not encouraging to the adoption of such a coarse. It will be remembered that so late as May, 1886, the General Committee of the Institution appointed a subcommittee to inquire into tho practicability of applying steam to Life-boats, which, after having examined the models of steam Life-boats exhibited at the Liverpool International Exhibition, and having heard the evidence of the coxswains of Life-boats on different parts of the coast who were best able to speak of the assistance to be obtained from steam in carrying out the Life-boat work, came to the conclusion that they were then unable to recommend the adoption of any pattern of steam Life-loot. Again in 1887 the Committee offered gold and silver medals for the best ! models or drawings of a steam Life-boat, 1 and the three most competent experts, entirely independent of the Life-boat Institution, who accepted the office of judges of the competing schemes, some of which came from the Continent and America, after full and careful examination, reported that they could not award any medals, because none of the models met the requirements of the Institution.

The next movement, which has resulted in the construction of the boat now under consideration, was initiated by Messrs.

B. & H. GBEEN, the well-known shipbuilders of Blackwall, who in the early part of 1888 laid before the Committee plans for the construction of a steam Lifeboat.

After various modifications had been introduced, which were the result of considerable consultation between Messrs.

Green, the Committee, and the professional officers of the Institution, the plans were finally adopted and the boat ordered to be built. These plans contained several peculiarities, if not absolute novelties.

The first place amongst these must, we think, be given to the method that was adopted for propelling the boat, viz., the much-controverted turbine, or hydraulic system. The alternative must have been the screw-propeller in some form, because paddle-wheels were obviously inadmissible for such a purpose.

The advantages of the screw would have been lighter engines and boiler, developing less horse-power to obtain the same speed in moderate weather and fairly smooth water, and consuming less fuel, thns increasing the steaming power of the boat as measured by the number of hours for which fuel could be carried. Against this had to be put the certainty of the propeller in a vessel of the unavoidably light draft of water indispensable for a Life-boat, being constantly lifted out of the water by the motion of the boat, even in an ordinarily rough sea, and very much more so in the seas a Life-boat is called upon to face, and to face successfully. A bird's-eye consideration of the duty of the screw and how it performs it, will, we think, make clear to the uninitiated the inevitable result of its being thus lifted out of the water. The screw (or screwpropeller), as its name signifies, forces the ship forward, or rather takes the ship forward or backward with it, by its action on the water, on exactly the same principle as a screw penetrates into a piece of wood, or a corkscrew into a cork, the power that enables it to do so being that exerted on it by the engines in the former case, and by the hand that turns the screw-driver or corkscrew in the latter. Water, of course, is not a so strongly resisting medium to the screw as the more solid wood or cork referred to, but it is a resisting medium, or no advance would be made by means of the screw. The consequences of lifting the screw out of the water, or resisting medium, with the power employed to force it through it being still exerted, are 1st, such a sudden increase in the motion of the engines from the resistance being withdrawn (technically called " racing") as endangers their breaking down unless at once checked. 2nd. All power to propel the vessel in the direction desired is lost on the withdrawal of the resistance to the screw which gave such, power. A screwpropeller also runs very considerable risk of injury should the boat strike the ground, and is very liable to be injured, and perhaps stopped working, by any floating wreck or ropes coming in contact with it.

The turbine, or hydraulic propeller, is in great measure free from these dangers, the speed of the vessel being practically obtained through the force exerted by a very powerful centrifugal pump, taking in its water through a supply-orifice in the bottom, and discharging it at the sides through outlets pointing in the opposite direction to that in which it is wished to propel the boat; so that so long as the orifice in the bottom is under water, and free to admit the required quantity, and the outlets in the side aie also free, the motion of the boat due to the action of the sea, however great, cannot check or diminish the steady flow of power being exerted to propel her, although it and the action of wind and sea will, of course, diminish the effect of that power to a certain extent, but not more than it would •were the boat propelled by a screw.

Another material advantage of the turbine consists in the greatly increased power of manoeuvring the vessel that it offers over that given by the screw. One of the principal reasons of this advantage is the facility with which the direction in which the water is discharged, eaa be changed, without interfering with the running of the engines or the working of the pump in any way.

As before said the motion of the boat is obtained through water discharged by the pump in a direction opposite to that in which it is desired to propel her. This direction is changed wholly or in part by means of a valve or shutter acting in the pipe leading from the pmaptothe outlets on each side of the boat. The position of these valves determines the direction of the outflow of the water on either side of the boat, so that the two sides can be discharging for going ahead, or one ahead and one astern, or one set stop and the other going ahead or astern, either full or slow speed, without stopping, or in any way interfering with, the working of the engines, and consequently the amount of water discharged by the pump. Of course the complete alteration of direction IB obtained by putting the valves so as to shut close the outlet for the opposite direction; partial alteration by putting the valve into such a position as to divide i the outflow throngh the two outlets in the proportion necessary to obtain the action on the boat that may be required.

To neutralize the action entirely, or to produce the position of the engines stopped, one half of the outflow is directed through each outlet. These valves are worked at will by handles on deck, and the action is so instantaneous that even when going between 8 or 9 knots an hour the boat is stopped dead in 13 seconds, and, when laying stopped, headway is obtained again in 4 seconds. The power above described is also efficiently available for turning the boat round whilst laying still in the water, or for steering the boat when either going ahead or astern, in case of loss of, or injury to, the rudder. Not only all seamen, but any one who may have watched the evolutions of laying a small passenger steamer alongside a pier, with the various stopping of the engines, and starting in opposite directions to obtain the desired position, will readily realize the immense advantage the power above described must be to a vessel employed on such work as that of a steam Life-boat, where rapidity of movement, combined! with facility for manoeuvring is a most requisite if not absolute sine qua, non, more particularly when, as in this case, the power is exerted without incurring any of the delays and possible uncertainty of action inseparable from stopping and starting the engines, for they continue on their even course, pumping out a volume of water without the slightest regard as to the direction in which it is going, or the action they are exerting through its agency on the motions of the vessel.

Against these great and most valuable qualities of the turbine or hydraulic principle of propulsion for the purposes of a steam Life-boat, must be placed the fact that in consequence of it not being so economical a speed producer as the screw, larger and heavier engines and boiler, developing considerably more horsepower, are necessary, to ensure the requisite speed; these are accompanied by the in - evitable greater coal consumption, and consequently shorter steaming capacity, as calculated by coal supply, as compared with a screw-propeller. In addition to these it may strike some people that the propelling power being dependent on the constant free admission of a large body of water throngh the intake (amounting, when working full speed, to a ton a second), the suction near the intake must be so great that it would be very liable to draw in any piece of wreck, etc., passing near it, and so cut off the supply either wholly or in part. Very exhaustive experiments fully described later on in this account, proved conclusively that so far from this being the case, the system ssed scathless through tests that could not have been applied to any other known propeller without stopping it.

We cannot but anticipate a general concurrence in the view of the Institution, that for purposes of a steam Life-boat there can be no comparison between the advantages to be obtained from the turbine as compared with the screw or any other known propeller.

The material selected for her construction was the very best steel that could be procured, and in making the various joints and attachments of the different parts, one third more rivets were put in than is usual in torpedo boats, or other small vessels of that class. Where a seam would have been double riveted in a torpedo boat it is treble riveted here, and there is not one single-riveted seam throughout the vessel. The total number of rivets nsed was 72,000. The vessel is divided into fifteen watertight compartments, all in connection with the bilgepumps and steam ejectors, of •which there are two powerful ones on board. Everything possible has been done to combine lightness and strength with great stability and seaworthiness. Her stability vanishes at 110°, that is to say, when the mast is sufficiently far below the surface of the water to make an angle with, it of 20° between it and the surface.

An interesting and convincing practical test of her stability that was made was heeling her over by means of a parbuckle and steam-crane, with all her weights on board and in their places, to an angle far nearer to her beam-ends than she is ever likely to be thrown at sea, and whence, had her stability not been still very great, as proved by the strain necessary to bring her there, she would have fallen over bottom up. Her length is 50 feet, her breadth—"moulded"—is 12 feet, her extreme breadth 14 • 3 feet, and her depth 3 feet 6 inches. Although not a self-righting boat, she is to a certain extent planned after them by having modified end boxes, on the same principle and partly for the same purpose answered by those of a self-righting boat, viz., to give buoyancy at the extremes in a heavy sea, and increased stability when thrown on her side, which fchey do by offering resistance to her going any farther. She is decked all over, and the necessary accommodation and shelter for the crew and passengers is obtained by lowering the deck in the space between the after end of the engine-room, and the after air-box from the level of the gunwale to about three inches above the water as in the Institution's self-righting boats. This space will hold from 35 to 40 people, and means are provided for freeing it from any water that may break on board, by valves in the deck in the ordinary way. The engines are of the horizontal direct-acting compound surface-condensing type, with cylinders of 8J inches and 14£ inches diameter, and a 12 inches stroke. The boiler is of Thornycroft's patent tubulous pattern, having a heating surface of 606 feet, and 8£ square feet of grate surface, loaded to 125 Ibs. Full speed is obtained by forced draught, the fan for which runs at about 1,000 revolutions a minute. At utmost speed the engines ran at about 430 revolutions, and the highest speed attained at the measured mile was 9-17 knots. Although considered per s« this is not a very high speed for the horse-power developed in & vessel of these dimensions, it is ample for the purpose required, and more than would be nsed against a heavy head sea, such as the Life-boat will have to encouuter, without the imminent risk of serious damage to both vessel and her crew, from the greatly increased force it would add to the blow of a breaking sea meeting the vessel. So far as the conditions of weather have hitherto permitted, her various qualities and fitness for the work she is intended for have been tested, but the boat cannot be said to have yet finally passed from the experimental stage, nor do we think she ought to be considered to have done so, until she has more than once successfully passed the crucial test of going off to outlying sands in a gale of wind and saving life. Ona very interesting proof of her qualities, or rather of the non-existence of a possible danger, is given by the experiments carried out to ascertain the liability of the inlet for the water to the pump to become choked by wreckage, etc. For this purpose three apparatus or traps were prepared for her.

No. 1 consisted of two pieces of boats' mast 6 feet long, attached to each other by a rope 24 feet long, having seven or eight pieces of rope alternately double and single, and each a fathom long hanging from it. No. 2 consisted of a rope 24 feet long, with pieces of irregularly broken wood, each about 2 J feet long, and from 2 to 4 inches in circumference attached to it at 2jj feet apart, reminding us much of the kite-tails of our boyhood very mnch magnified.

No. 3 consisted of a boat's sail.

Whilst steaming down the Thames, for the purpose of carrying out these tests, a large number of pieces of wood of various sizes and old grass sugar bags were fallen in with; the boat was directed over them so that a large number of pieces were fairly struck and pressed down by the stem; with the result that none were drawn into the intake but all passed clear. Nos, 1 and 2 arrangements, although thrown overboard several times in each a way as to ensure their passing the intake whilst the engines were working, entirely failed to affect it. No. 3, the boat's sail, when put over the bows and held there whilst the boat was steaming ahead long enough to ensure its being laid out fiat under the bottom and then let go, did choke it, bnt when thrown overboard and the boat steamed over it, quite failed to do so.

We think this notice of the steam Lifeboat -would be incomplete and possibly misleading to many of our readers, without some slight forecast of the probable effect this experiment, if completely successful, will have oa the organisation and propulsion of the Institution's fleet.

The conditions under which the work of the Life-boats of the Institution is carried out, inevitably vary with the position and requirements of each station, and may be fairly classified as follows:— 1st. Boats kept afloat at moorings for service principally on outlying sands.

2nd. Boats launched from the beach for service on outlying sands.

3rd. Boats launched from slipways specially constructed for the purpose, for service on either outlying sands or the main shore.

4th. Boats on carriages for transporting to any part of the shore, to be launched from the carriages into the surf, and principally required for wrecks on. or near the main shore.

The great unavoidable additional weight entailed by the engines, boiler, coalsupply, etc., would render steam quite inapplicable to class 4, which comprises about four-fifths of the total number of the fleet, and in which weight, both as it affects the land transport and the draft of water, is a matter of vital importance, indeed, to such a degree is it so, that it often governs the dimensions of the boat to bo given to a station.

The same difficulty would also hold good in class 2, the weight being entirely prohibitory.

In class 3 the conditions and requirements vary so much that there are very few, if aay, stations to which steam would be suitable. This leaves ouly class 1, which comprises a very small number of boats.

Another important element of the question which must be considered, in administering the funds of an Institution entirely supported by Yoluntary Contributions, is the enormous increase of expense inseparable from the building and maintaining of boats such as we have been describing..