it to be instantly secured and made fast. Beyond this, under the said condition — i.e. head to wind — it is only in the exceptional case of a heavy cross sea that the rolling could be serious, and with the modern methods of steadying sea-going vessels (gyroscopes and ballast-tanks) it would require a quite exceptional state of weather to keep the air fleet imprisoned. There is one constructional point worthy of mention; the flying-deck will require to "run-out" at the bows of the ship in easy lines, to avoid setting up eddies or dead regions, such as might affect the stability or buoyancy of machines landing or leaving the deck; to some extent it may be found necessary to extend this precaution to where deck joins gunwale abeam.
It is also worthy of note that the proposed pontoon-ship, being of comparatively light draught and great beam, will possess naturally the type of stability of a raft rather than that of an ordinary ocean-going vessel, and will thus tend in a seaway to follow the changing slope and motion of the long ocean waves. Now this slope and motion, as is well known, are so co-ordinated that the normal to the wave slope is always the apparent plumb, and so it may even turn out that the flying-machine, on taking the deck of a vessel studied as a raft rather than as a ship, will (even when the motion is severe) have no tendency either to side-slip overboard or turn turtle.
The same conditions which are favourable to alighting, as from the point of view of relative motion, are also favourable to the machine when getting away. Thus, with a 40-mile-per-hour wind and a vessel at full speed, head to wind (as already assumed), a machine will be able to leave the deck with a relative motion of only some 10 or 20 miles per hour and a flight velocity of 70 or 80 miles per hour. Taking all the possibilities of the
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