Advance In the Motor Life-Boat
THE last article on the Installation of the Motor in Life-boats appeared in The Life-boat Journal, VOL XX., No. 225, published in August, 1907, and it will it is thought be of interest to our readers if we review the progress made since that date in the adoption of power, which must undoubtedly in the future be an enormous factor in the facilities for saving life at sea.
At that time(1907)our motor-boat fleet consisted of the following experimental boats, installed with petrol motors :— Walton-on-the-Naze, Norfolk and Suffolk type, 43 ft. by 12 ft. 6 in. with a 4-cylinder " Blake " of 40 B.H.P., 550 revolutions, diameter of cylinder 5J in., length of stroke 6 in., and approximate weight 16 cwt. This boat was fitted with a reversing clutch, and attained a speed of 6 • 6 knots per hour on a con- sumption of petrol of 20 • 4 pints.
Newhaven self-righting type, 37 ft.
by 9 ft. 3 in., with a 4-cylinder Thorny- croft, 24 B.H.P., 1,000 revolutions, 4£ diameter of cylinder, 5 in. stroke, and approximate weight 8 cwt., fitted with a reversing clutch, and attaining a speed of 7 • 2 knots per hour on a consumption of petrol of 15-8 pints; and the late Ramsgate Life-boat self-righting type, 42 ft. by 11 ft., with a 4-cylinder "Tylor" (originally called "Briton"), 30 B.H.P., 900 revolutions, diameter of cylinder 5 in., length of stroke 5 in., approximate weight 8 cwt., fitted with a Buffalo clutch, attaining a speed of 6 • 8 knots per hour on a consumption of petrol of 18-5 pints; and also the first experimental boat, an old self-righter, 38 ft. by 8 ft., installed with a 2-cylinder motor of 10 H.P., which was described in The Lifeboat Journal in August, 1904, and which boat is still doing good work at Tynemouth.
All four of the above boats were converted, which necessitated consider- able structural alterations to adapt them for power, and after exhaustive ex- periments had been carried out the Committee of Management, in 1907, considered the time had then come to go further ahead, and ordered four more motors for boats specially built to receive them.
This latter was an all-important point, inasmuch as adaptation could not pro- duce the perfect article, but proved invaluable to the Institution in arriving at the necessary data required in future installation, and it must be conceded that the results have fully justified the experiment.
An interesting feature in the con- struction of the new boats has been the position selected for the propeller, and by reference to the sketch plans it will readily be seen the following difficultiesare met so far as it is possible to do so :— 1. Racing of the motor in a seaway.
2. Working the boat on a slipway.
3. Partial immunity from fouling by wreckage and other causes.
Dealing with these points in order, we must consider that of the danger of racing. A Life-boat, when in the open sea or in breaking water, must necessarily be of such a buoyant description that her bow and stern are frequently lifted out of the water, so that to place the propeller near the sternpost, as is usually done in vessels and boats, would cause so much racing, that no matter how well-governed the motor might be there would be undue strains imposed, and also, a very important matter, the loss of power when most urgently required.
It therefore became a necessity to select a spot most favourable for this, and as will be presently seen to sur- mount other obstacles. The natural answer to this was to place the propeller as far forward as possible, and the spot selected has been just forward of the after end-box; but it was obvious when we come to the question of working the boat on a slipway, the propeller must be not only above the keel, but entirely protected from any possibility of damage when both leaving the slipway and in re- housing her on her return from her work, which latter has frequently to be done under great difficulties, due to windage, tides and movement in the water.
This resolved itself into a tunnel, which is constructed of mahogany, and is of a turtle-backed shape, rising from the top of the iron keel, com- mencing from a position" at about one- third of the length of the boat from her sternpost, and extending back in a gradual curve to the sternpost, a hatch being provided in the deck of the boat to enable ready accessibility to the pro- peller boss and blades. In this tunnel then the propeller does its work. The effect of racing has been very materially reduced ; any possible difficulties to be met with when dealing with a slipway have been overcome; and lastly, and not the least important, partial immunity from the fouling of the propeller arising from wreckage alongside a vessel, pier ropes, and the hundred and one matters liable to cause this and put the motor out of action, has been provided.
However, on several occasions on the coast the writer has been questioned as to whether the propeller doing its work in the tunnel does not mean a certain percentage of loss of speed, owing to its revolving in a smaller body of water than is the case when in the usual position found in all classes of vessels, and undeniably this is so to a certain extent; but whatever that loss may be, the advantages shown in the preceding paragraphs are of such paramount im- portance that this loss of speed will be readily accepted by all Life-boatmen who have already felt the advantages of having a motor under their lee.
Again our readers must bear in mind that the Committee of Manage- ment have in no way departed from their primary decision that the motor must be considered solely a means of auxiliary propulsion, the same area of canvas, and the same facilities for pull- ing being supplied to all boats, although as to the latter,, some loss of oar power must necessarily ensue, owing to the space required for the motor hatch.
In the larger boats this really is- of minor importance, as it cannot be expected that oar power can be of any great value, except for an emergency.
The four motors ordered were allocated to the following boats :— Sironsay.—A. " Watson " type, 43 ft.
by 12 ft. 6 in., a 4-cylinder « Blake " of 40 B.H.P., 600 revolutions, diameter of cylinder 5 • 3 in., length of stroke 6 • 29 in., and approximate weight 15 cwt., with a Gaines reversing propeller.
Stromness.—Self-righting type, 42 ft.
by 11 ft., a 4-cylinder "Tylor" of 30 B.H.P., 800 revolutions, diameter of cylinder 5 in., length of stroke 5 in., and approximate weight 10 cwt., with a Villinger propeller equipment.
Fishguard.—Self-righting type, 40 ft.
by 10 ft. 6 in., a 4-cylinder " Tylor " of 24 B.H P., 650 revolutions, diameter of cylinder 5 in., length of stroke 5j in., and approximate weight 10 cwt., with a Meissner propeller equipment.
of cylinder 5 in., length of stroke 5J in., ajid approximate weight 13 cwt., with a Villinger propeller equipment.
The first two of these boats were completed and despatched to their northern homes last April. The Stron- say boat on her trials attaining a speed of 7 • 2 knots per hour on a consumption A3xi2-6 WATSON TYPE BOAT.
INSTALLED WITH 40 B.H.P.MOTOR FlQ.3 FIG. A.
FIG.5.
FIG. 1.—ELEVATION SHOWING MOTOR, PROPELLER AND TUNNEL.
PIG. 2.—PLAN SHOWING MOTOR HATCH, PETROL TANKS ON FORE SIDE, CONTROL WHEEL AND STEERING WHEEL.
FIG. 3.—SECTIONS OF APTEB BODY SHOWING TUNNEL.
FIG. 4.—SECTIONS OF FORE BODY.
FIG. 6.—MIDSHIP SECTION.
Thurso.—" Watson " type, 40 ft. by 11 ft., but this station, foregoing her claim owing to local difficulties being foreseen in the future, it was decided to transfer the installation to another boat of the same type and dimensions being built for Broughty Ferry, and the motor selected for her is a 4-cylinder " Tylor " of 40 B.H.P., 600 revolutions, diameter of petrol of 25 pints and the Stromness boat 6'7 knots per hour on 21 pints.
An account of the passage of these boats to the Orkneys appeared in our issue of last August, the crews of both having been loud in their praises of the benefits derived from the motive power; and this recalls to the writer a very com- prehensive remark made by a northernfisherman when out for exercise in an ordinary sailing Life-boat. The topic was motor power, and the stroke oar, hearing the Stronsay boat mentioned, glanced upwards, and, with great admiration, expressed himself as follows : " Ay, mon, but yen's a bonny boat"; and there's no doubt he hit the truth.
The third of the quartette shortly followed on their heels, and went through her ten days' sea trials at Harwich last August. These were very severe, being carried out in very heavy weather, but throughout she gave no trouble, acquitting herself to everybody's satisfaction.
On these trials a special point was made in testing the admission of air to the motor casing—it will be readily seen that when a motor Life-boat goes to sea, the casing must be battened down and rendered absolutely water- tight. To ensure this it must be also air-tight, and consequently some of our readers may wonder how the motor breathes, this being as essential to the motor as to the human frame. The explanation is simple. The air is sucked into the casing by pipes leading to the after end-box, which is provided with an automatic ball-valve in all boats for ventilating purposes. In the ordinary floating position of the boat, this valve is always open, but should the boat capsize the ball falls into the valve automatically and prevents the inrush of water, so that in any case the motor hatch is kept free of this undesirable commodity. On these trials in heavy weather, this hatch was kept practically sealed down, and when opened at the end of a five hours' run, not only was the motor running perfectly, but all the running parts were as cool as could be desired, there being only slight warmth in the bearings due to generated heat.
On her speed trials she attained a speed of 6-8 knots on a petrol con- sumption of 22 pints per hour.
On completion of the trials, she remained at Harwich while arrange- ments were made for a navigating crew to come from Fishguard. She was finally despatched to her station on the 14th October last, in charge of the Inspector of the Western District, Lieutenant E. D. Drury, R.N.R., the voyage proving an extremely valuable experience, much bad weather and very heavy seas being met with during the passage, and cer- tainly a very trying one to the hardy occupants of the boat. Throughout the voyage of 583 miles no hitch of any kind was found, the motor proving itself thoroughly reliable, and giving all the satisfaction that could be possibly desired.
Mr. William Small, the Assistant Surveyor of Motors, who had charge of the motor on this voyage, makes some very interesting remarks on the merits of the motor, especially as regards the governed engine, reporting that, on the run from Yarmouth (Isle of Wight) to Weymouth, on which occasion they experienced a S.W. gale accompanied by a high head sea, the governed engine proved its merits, as when passing through the heavy race off St. Albans Head, the propeller on two occasions was half out of water, the speed of the engine in an instant being reduced to 250 revolutions, and as the load came on again the governor gently opened the throttle, allowing the engine to run at its proper speed.
Had it not been for the activity of the governor on the different loads, when the boat was thrashing her stern, there would appear to have been every possibility of her shedding her propeller.
In addition to the Broughty Ferry boat, which is not yet completed, motor boats are being built for the following stations :—Donaghadee, Wicklow, St.
Abbs, Seaham and Tynemouth.
Of these latter, the Donaghadee boat is in a final stage of completion. She is of the "Watson" type, 43 ft. by 12 ft. 6 in., with a 4-cylinder " Blake " of 40 B.H.P., 600 revolutions, diameter of cylinder 5| in., length of stroke 5£ in., approxi- mate weight 12 cwt..