"Very good," was the rejoinder.
Broadmayne saluted and went off to make the necessary preparations.
The Canvey was equipped with two types of diving dresses, both designed and made by the firm of Siebe, Gorman & Co. One was of the common variety, in which the air is pumped through a pipe from a pump above the surface of the sea. The other was of the self-contained type; the air supply, judiciously combined with oxygen, is contained in cylinders strapped to the back of the diver. Thus he is independent of air-tubes, life-lines and other contrivances likely to impede his movements.
The Sub chose the latter type of dress. The depth in which the Alerte had sunk was between fifty and sixty feet at low water, the maximum distance below the surface at which the self-contained diving-suit can be used without undue risk.
One of the seaman-divers was already being garbed in a similar suit by his attendants; the other man was preparing to don a dress with lifeline and air-tube, the helmet being provided with a telephone by means of which he could engage in conversation with the above-water party in the boat.
The descent was to be made as speedily as possible before more sharks appeared upon the scene of the wreck to feast on the bodies of their less fortunate kind who had been killed by the explosion. Nevertheless, Broadmayne and his companions were warned to keep a sharp look-out while under the surface. As a rule, a shark will hesitate to attack a diver, but there have been instances in which a terrible submarine struggle has taken place between a diver and the tigers of the deep.
The diving-boats pushed off and anchored fore and aft as close as desirable to the wreck. The diver with the air-tube type of dress was the first to descend, sliding at a steady pace down the shot-rope.
A tug on the life-line gave the attendants warning that the man had reached the bottom. "Ready, sir?" asked a petty officer.
"Right," replied Broadmayne.
The glass plate in the front of his helmet was screwed home. He was now cut off from the outside world as far as the air supply was concerned, and the sensation was not a pleasant one.