THE first life-boat to be fitted with diesel engines was completed in 1936, and since 1952 diesel engines have been installed in all new life-boats. Never- theless, there are still an appreciable number of life-boats in the fleet which have petrol engines. These older boats are in themselves thoroughly sound, in all respects seaworthy and excellent as life-boats, and the Institution has given much thought to the problems of their modernisation in order to make the best use of them. An experiment has recently been carried out in replacing the petrol engines of an existing life- boat with new diesel engines. The life- boat chosen for this experiment was the 41-foot Watson type boat built in 1939 and stationed at Port Erin in the Isle of Man.

The advantages which it was hoped would be achieved were to increase the life-boat's speed and power, extend her radius of action and increase the life of a perfectly sound hull.

Some increase in Speed Clearly no great increase of speed could be expected from the existing hull form which embodies all the essential qualities needed in a life-boat. But it was thought that by installing new engines and propellers some increase in speed should be obtained and that there would be a marked increase in the radius of action. In fact the horse power was increased from twin 36 h.p. to twin 47 h.p. engines; the radius of action at full speed was raised from 64 miles to 94 miles, and the speed was increased from 8.12 knots to 8.57 knots.

To achieve these results a number of modifications had to be made. The pitch of the propellers was made slightly coarser, and it was decided to use a different material for the propeller shafts in order to absorb successfully the increased load. The choice for the new material lay between stainless steel and monel, and the latter was chosen.

Among other advantages resulting from the choice of monel may well be the elimination of corrosion in the form of de-zincification of exposed parts.

One of the major problems which the Institution has had to face in more recent years has been that of providing the necessary spare parts for these petrol engines. Commercial firms find small numbers of specialised spares un- economical to produce and this has necessitated the manufacture of these essential items at the Institution's depot.

The use of standard commercial marine engines virtually eliminates this im- portant problem.

Once the decision had been taken to fit diesel engines into the Port Erin life- boat, the choice of the most suitable type of engine still demanded careful thought and comparison. The overall weight of the new installation, the main dimensions and the centre of gravity of the engines all had to remain nearly the same. Water-cooled side exhausts were fitted in lieu of the stern exhaust installation that was in use with the petrol engines, and the original engine bearers were adapted to take the new engines.

The substitution of diesel for petrol engines in an existing life-boat was an engineering problem. The solution of this problem was, however, accom- panied by major changes in the manner of operating controls, which may have far-reaching consequences. Ever since motor life-boats were first built close consideration has been given to relating the control of their motive power to prevailing practices among fishermen.

Many life-boat coxswains are them- selves fishermen, and more than once it has been found that devices and methods used in small fishing boats can with the necessary modifications be adapted for use in life-boats.

A number of fishing boats today have the single-lever system, which permits the boats to be manoeuvred and their speeds to be controlled by the man at the wheel, who is himself some distance from the engines. In the Port Erin boat it was decided to introduce a similar system. This meant that the coxswain at the wheel could assume full control of the engines, while one mechanic could operate the radio transmitter and the other concentrate on the gauges and instruments. Alternatively a mechanic could stand alongside the coxswain and himself operate the controls from this position. The system of single-lever control is comparatively simple to install with engines which have a hydraulically operated gear; the change from neutral to ahead or astern can be effected by the simple movement of a cock or valve remotely operated by wire and pulley or light rod gearing.

Among other problems to which solutions had to be found before the installation of the diesel engines could be regarded as a complete success were those of quick starting in order to avoid running down the batteries. In life-boats an alternative method of starting en- gines has to be provided to insure against the danger of a failure in the electric system. The alternative method in the re-engined Port Erin life-boat is a two-ended system of hand cranking.

Because of the constant increase in electrical equipment installed in life- boats the drain on the batteries and dynamo is inevitably great. Life-boats often have to proceed at very low speeds during a prolonged search, using all their electrical devices. This tends to produce a rapid run-down of the batteries, and unless the dynamo has a reasonable output at low revolutions the consequences can be dangerous. The new engines in the Port Erin boat have their dynamos driven by a V belt and pulley carefully selected to meet these particular needs. The dynamos fitted in this life-boat have an adequate output to meet present needs with a reserve for possible future requirements.

The final choice of diesel engine was made after an examination of a wide variety of those engines already on the market. There were in fact compara- tively few engines satisfying the parti- cular requirements and dimensions of this type of life-boat, and in the end the choice made was that of a Parson/Ford Porbeagle engine developing 47 h.p. at 1800 r.p.m., or 52 h.p. at 2,000 r.p.m.

There is a 2—1 reduction gear with both engines, but the port propeller is handed in rotation by means of an additional wheel in the gear box.

It is the regular practice of the Institution to send a new type of life- boat, or a life-boat in which there are novel features of major importance, on a long trip round the coast before she goes to her station so that first-hand evidence can be gained of how she reacts to different sea conditions. The Port Erin life-boat, after her conversion had been compJeted by Messrs. Wm. Osbornes Ltd. of Littlehampton, sailed for Rams- gate on the 28th October, arriving at Port Erin on the 7th November. On the passage to her station she called at the life-boat stations at Gorleston, Humber, Teesmouth, Berwick and Aberdeen.

She then sailed through the Caledonian Canal and called at Oban and Campbel- town on the last leg of her trip. This totalled 889 miles, and the fuel con- sumption for the passage was 3.88 gallons per hour or 1.8 miles per gallon.

With the original petrol engines it would have been approximately 1.1 miles per gallon.

Inspectors' Reports In the course of her passage the Superintendent of Depot and a number of the Institution's district inspectors and district engineers reported on her performance.

The Superintendent of Depot, Com- mander E. W. Middleton, reported that he was very favourably impressed with the engine controls and wrote: "The engines ran faultlessly and appeared to have perfect driving power. The cox- swain and crew all appeared to be delighted with their re-engined boat." The Northern District Inspector, Lieut.-Commander Roden, who during his passage encountered gales of force 9, described her as "an excellent sea boat." Similar comments were made by the other district inspectors. The Eastern District Inspector, Lieutenant E. D.

Stogdon, for instance, wrote: "An excellent job has been made of re- engining this boat. Her speed through the water was a good 8.5 knots and there was a fine feeling of getting some- where at that speed in so small a boat.Having tried the engine controls by the wheel, I can report that I am fully in favour of this arrangement." The Central District Inspector, Commander L. F. L. Hill, wrote: "While taking this boat on passage I found that the new engines and remote control behaved perfectly. Once the coxswains have handled this system they like it very much indeed." On the 30th January, 1962, after the life-boat had been for some time on service at her station at Port Erin, and her regular crew had had further experience of her, the honorary secre- tary of the station, Captain G. D.

Madrell, wrote to say how very pleased the branch were with the performance of the boat. On the 15th January the life-boat was out in very heavy weather, and the crew expressed their complete satisfaction with her..