128 THE MARINE ENGINEER. [ July 1, 1888.

EXHIBITS OF MESSRS. ALLEY & MACLELLANAT THE GLASGOW EXHIBITION.

MESSRS. ALLEY & MACLELLAN, of the SentinelWorks, Glasgow, have on view a very fine display

Of the accompanying illustrations of the “Sentinel” steam steering-gear Fig. 1 shows an end elevation, and Fig. 2 a side elevation of a gear suitable for a vessel of 3,500 tons gross, the outside dimensions of which are, extreme length, fore and aft, 6 ft. 3 in.; extreme breadth, athwartships, 4 ft. 6 in. Truly a small enough deck space for a gear capable of putting the rudder of such a ship from “midships” to “hard over” in seven seconds.

The illustrations give a good general idea of the gearwhich, as will be seen, may be either steam alone, or steam

and hand combined, and in either case independentsteering may be effected from any convenient station inthe ship; thus, in the example shown, a small hand-wheelis fixed on the bridge immediately over the gear.

Without going into further details we will briefly enumerate some of the advantages of Messrs. Alley and Maclellan’s “Sentinel” gear.

Everyone has heard that steam gears can eat up too much steam, and that a steam-steered vessel is either too sluggish in her courses (due to the slowness of the gear used in reversing) or flies to the opposite extreme, by the gear’s running away when once reversed.

Now the first defect can only be attributed to badly designed valve arrangements, which soon become leaky, and the second to bad reversing gear. In the “Sentinel” the valves are so constructed that they take up the wear of the faces automatically, and they will work to the end without leaking, thus getting over the first objection. Second, in the “Sentinel” the reversing action is very sharp, the movement in either direction of the wheel to the extent of one spoke reversing or stopping the engine, and this allows of the “Sentinel” being used at sea with perfect confidence. In addition to this the “ Sentinel ” gear is

of their various specialities, including examples of “Sentinel” steam steering gear for vessels from 500 to 5000 tons register, a typical form of which we illustrate herewith; “Sentinel” ash hoist; “Sentinel” reversing engine; also a Westinghouse high-speed engine and dynamo, a Westinghouse ordinary engine, and a large assortment of steam and water valves and fittings.

FIG. 2.

FIG. 1.

129THE MARINE ENGINEER.July 1, 1888. ]

quite noiseless, no spur gearing being used in its construction.

Only the very best materials are used in the construction of these gears, and the workmanship leaves nothing to be desired, and as no gear leaves the works without a ten hours’ absolute trial, they may be relied on to perform well when afloat.

Amongst others who have fitted these gears we may mention Sir W. G. Armstrong, Mitchell & Co., for the Italian Navy; Bengal and North Western Railway Co.; Palmer’s Shipbuilding and Iron Co., Jarrow; Gourlay Bros.; M’Ilwaine, Lewis & Co.; Withy & Co.; Napier, Shanks & Bell; Archd. M’Millan & Sons ; Simons & Co.; R. Duncan & Co.; Grangemouth Dockyard Co.; Scott and Co., and Russell & Co.; all of whom have given repeat orders for the gear, while single orders have been given by, amongst many others, Messrs. W. Denny and Bros.; Swan & Hunter; Oswald, Mordaunt & Co.; Hawthorn, Leslie & Co., &c.

Perhaps the next most interesting exhibit (to marine engineers) on Messrs. Alley & Maclellan’s stand is their “Sentinel” ash hoist, and as we intend illustrating this in our next issue we will only briefly notice it here. Its chief feature is an arrangement to prevent overwinding the buckets, always a source of danger with the ordinary winding arrangements, and so perfectly does it do its work that it is impossible to overwind with it. We may mention that it is already in use on board vessels of the English, Italian, and Spanish Royal Navies, and also in a number of large steamers.

The “Sentinel” reversing engine, for working the reversing gear of large marine engines, is a very neat and compact machine, fitted with the same arrangement of valve gear as the steering gear, by which an absolutely certain and quick reversing action is ensured.

There are many interesting exhibits on this firm’s stand, and no marine engineer ought to visit the exhibition without inspecting them.