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A Steam Life-Boat for South Holland

THE South Holland Life-boat Society was so pleased with the result of its inquiries as to the success of the NATIONAL LIFE- BOAT INSTITUTION'S Steam Life-boats that it recently instructed Messrs. J. I. Thornycroft and Co., of Chiswick, to build for it an hydraulic Life-boat precisely similar, as regards machinery, to the Insti- tution's Steam Life-boat Duke of North- umberland, the hull being designed by Mr. Gr. L. Watson, the consulting naval architect of the Institution. The boat, which is named the President van Heel, is built entirely of steel, and her dimensions are as follows:—lengths, over all, 55 ft.; on the water line, 53 ft.; breadths, moulded, 13 ft. 6 in.; over sponsons, 15 ft.; and extreme, 16 ft.; the moulded depth being 5 ft. 6 in. She has an extreme water draught, when fully loaded, of 3 ft. 3 in.; the load consisting of crew, four tons of coal, mast and sails, some 30 or more passengers, and her tanks full of fresh water, which, with the propelling machinery and boiler, give her a dis- placement of about 30 tons. The hull of the boat is divided into 18 watertight compartments, two of which are occupied by the engines and boiler and two forming the coal bunkers, each being capable of being freed of water—the smaller by means of a portable deck pump and the larger by the main engines.

The propelling machinery consists of a compound surface - condensing engine, driving direct a nearly horizontal centri- fugal pump, the impeller of which (30 in. in diameter) delivers the water with which the pump is fed, by a scoop-shaped inlet amidships, through four nozzles or outlets in the sides of the boat, two for motion ahead—one on either side—being placed below the water aft, and those for motion astern close under the sponsons, above water, forward. The engine has no reversing gear, but is always running one way, the direction of the boat ahead or astern being controlled by valves in the discharge pipes from the centrifugal pump.

These controlling valves can be worked either from the engine-room or by the coxswain at the steering wheel, and by moving one valve only the boat may be made to turn round on her centre, and may consequently be steered independently of the rudder. The boiler for supplying the engines with steam is one of Mr. Thornycroft's patent water-tube type, and is capable of supplying ample steam at a pressure of 145 Ibs. per square inch to enable the engines to develop about 250 indicated horse-power.

The Life-boat is steered by an ordinary deep rudder, which is moved by simple worm gearing, and fitted with an arrange- ment for tricing it up in shoal water, without interfering with steering opera- tions. For working the anchor and warping purposes, a steam capstan, driven by an independent engine, is fitted at the after end of the engine-room, a reel of 100 fathoms of flexible steel-wire rope being fixed in the cockpit or well of the boat. To assist the propelling power and the steadying of the boat it is fitted with a mast hinged in a tabernacle forward, which when not in use is lowered and stowed along the covering of the machinery.

When in use it carries a lug sail and staysail.

The new Life-boat, on the 19th September, underwent a series of official speed-trial runs on the measured mile in the Long Reach on the River Thames, followed by some manoeuvring tests to determine her handiness and steering capabilities.

Six continuous runs were made, with and against the tide, with results as shown in the table opposite.

From this it will be seen that the mean speed attained over the whole of the runs was 9 • 294 knots, or fully three-quarters of a knot in excess of that guaranteed by the builders, which was 8J knots in the fully-loaded condition, the assumed -weight of thirty passengers—on the trial—being made up with dead weight in the shape of iron kentledge.

Runa. B :i is cfi ii Ol3 l?| S OJ fl aW CQW M.S. 1. With tide . 541 10-557 9-287 2. Against tide 729 8-018 9-302 9-318 3. With tide . 539 10-619 9-298 9-279 9-294 4. Against tide 734 7-930 9-269 9-259 5. With tide.. 540 10-588 9-308 9-357 6. Against tide 7 23 8-126 The above results in speed were attained with a steam-pressure in the boiler of 140 Ibs. per square inch, maintained with an air-pressure in the stokehold equal to 2f in. of water, the power developed by the engines, which were running at a mean of 449 revolutions per minute, being about 220 indicated horse-power. After the speed-trials the Life-boat was tested in turning evolutions with and without the use of the rudder, and it was espe- cially remarked how easily she was put about or her head put in the desired direction quite independently of that directing instrument. A final test was made of the command of the helm and manoeuvring facilities possessed by the boat in the casting of a life-buoy to an assumed man overboard. The moment of throwing the buoy being noted, it was found that the boat, which was travelling at a considerable speed through the water, had been put about and the buoy re- covered in one minute of time.

We wish this new steam Life-boat " God speed " in her mission of mercy.