Courtesy of International Marine Engineering.
Mr. Lake then sent the _Argonaut_ to a Brooklyn shipyard, where her original cigar-shaped hull was cut in half, and lengthened twenty feet, after which a light ship-shaped superstructure was built over her low sloping topsides. To keep it from being crushed in by water pressure when submerged, scupper-like openings were cut in the thin plating where it joined the stout, pressure-resisting hull, so that the superstructure automatically filled itself with sea-water on submerging and drained itself on rising again. Though uninhabitable, its interior supplied useful storage space, particularly for the gasoline fuel tanks, which, as Mr. Lake had already discovered, gave off fumes that soon rendered the air inside the submarine unbreathable, unless the tanks were kept outside instead of inside the hull. The swan-bow and long bowsprit of the new superstructure, together with the two ventilator-masts, gave the rebuilt _Argonaut_ a schooner-like appearance, and her bowsprit has been compared to the whip-socket on the dashboard of the earliest automobiles. But Mr. Lake declares that this was no useless leftover but a practicable spring-buffer to guard against running into submerged rocks, while the bobstay helped the _Argonaut_ to climb over the obstruction, as she could over anything on the sea-bottom she could get her bows over.
Primarily, the superstructure served to make the submarine more seaworthy as a surface craft. Until then, most inventors and designers of undersea boats had confined their attentions to the problems of underwater navigation only, because, as had been pointed out by the monk Mersenne before 1648, even during the most violent storms the disturbance is felt but a little distance below the surface. But Mr. Lake realized that a submarine, like every other kind of boat, spends most of its existence on top of the water and that it is not always desirable to submerge whenever a moderate-sized wave sweeps over one of the old-fashioned, low-lying, cigar-shaped vessels. With her new superstructure, the _Argonaut_ rode the waves as lightly as any yacht and ushered in the era of the sea-going submarine.
It was not until a year later that the _Narval_, a large double-hulled submarine with a ship-shaped outer shell of light, perforated plating, was launched in France. She was propelled by steam on the surface and by storage batteries when submerged. To distinguish this sea-going torpedo-boat, that could be submerged, from the earlier and simpler submarines designed and engined for underwater work only, her designer, M. Labeuf, called the _Narval_ a “submersible.” As the old type of boat soon became extinct, the distinction was not necessary and the old name “submarine” is still applied to all underwater craft. That Simon Lake and not M. Labeuf first gave the modern sea-going submarine its characteristic and essential superstructure is easily proved by dates. The _Narval_ was launched in October, 1899, the _Argonaut_ was remodeled in December, 1898, and on April 2, 1897, Mr. Lake applied for and was presently granted the pioneer patent on a “combined surface and submarine vessel,” the space between its cylindrical hull and the superstructure “being adapted to be filled with water when the vessel is submerged and thus rendered capable of resisting the pressure of the water.”