§ 83. The Pontoon-Ship, Specification. The above list of requirements indicate at once that the pontoon vessel will need to be a ship of very large size, comparable to that of a first-class battleship, at least as ta length and beam. Beyond this, taking the requirements in order, there appears to be nothing really difficult or impossible of fulfilment. Thus, conditions (1) and (2) could be met without difficulty by a specially-designed vessel of a few thousand tons displacement. Condition (3) is more exacting, and requires that the vessel should be of the maximum beam admissible—say 90 ft.—with a water-line of not less than 500 ft.; also the need for doing away with funnels probably means that the internal-combustion engine will have to be considered as the means of propulsion. This, for the horse-power required—about 15,000 indicated—is rather beyond anything yet attempted; however, it can be by no means deemed impossible. The conditions could be met by employing six propeller-shafts, each driven by a Diesel unit of 2,500 indicated horse-power; this is not regarded as by any means beyond the limits of commercially sound engineering. The present day uses of the masts of a warship are mainly for signalling (by wireless and otherwise), to serve to carry searchlight and lookout platforms, and as an anchorage for jib-cranes. All these various requirements will need to be met without hampering the flying-deck with any permanent obstructions. Thus it is well understood that the "aerial" for a wireless installation may be arranged horizontally; in the present case it could be carried on spar outriggers, some 10 ft, or 15 ft, away from the gunwale, being shipped and unshipped as needed. Searchlights could, without difficulty, be mounted on telescopic pillars dropping flush into the deck, operated by hydraulic power or other means, and taking but a few seconds to raise or lower;
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