Submarine Appliances And Their Uses
Deep Sea Diving, &c., &c.

But it is evident that we must provide for the case of the boat being holed high up, and this can be done by the provision of bulkheads so arranged as to trap the air. (See illustrations on pages 86, 87 and 90.) The fitting of air-traps does not in any way impair the habitability or efficiency of the vessel, and all the newer submarine l3oats in the British Navy are so fitted, whilst the older types also are being converted. On one occasion, when a vessel, fitted with an air-trap, was accidentally sunk in a dock, two men escaped by means of the air-trap, without any helmet, but this was in shallow water, and the fore-hatch was open. Method of training men in the use of the Patent Sub- marine Life-saving apparatus at H.M. Dockyard, Ports- mouth. Copyright. THE APPARATUS AS A SHALLOW WATER DIVING DRESS, AND SMOKE HELMET. The same apparatus makes an efficient shallow-water diving dress, but since the conditions of use are altered, the object in the case of life-saving being to carry tbe wearer to the surface, whilst in the other case it is to keep him under water, it becomes necessary to weight him. For this purpose the ordinary diver’s boots and a weighted belt are provided, as shown in photo No. 47. As a shallow-water diving dress the apparatus can be used for about forty minutes, at a maximum depth of twenty-five feet, on one charge of the oxygen-producing compound. Thus an adequate time is allowed for the majority of the emergency cases where such apparatus is likely to be employed, such as examining or clearing propellers, clearing Kingston valves, examining hulls below the water line, recovering articles lost overboard, etc. As a SMOKE Helmet (see photo No. 48), tbe apparatus can be used for hard work for about forty minutes on one charge, or for light work for about one hour.