The surface vessel being properly moored, the ballast compartments are flooded and the working end of the apparatus allowed to settle near enough to the wreck to permit of inspection through the "aquascope," or the bottom door may be opened and divers sent out for more intimate inspection, and instructions may then be telephoned to the surface vessel so to change her position that the working compartment may be located in the place most convenient to act as a base for carrying on the operations of recovering cargo, making repairs, etc., as the occasion may demand. The position of the operating chamber may be over the hatchway of a ship, or, in the case of an old and worthless hulk, the decks may be blown off and the working end of the apparatus lowered right down through and on to the cargo itself. Sufficient additional water ballast may now be introduced to hold the working chamber securely to the bottom, or it may be held fast to the hulk itself, if that course be preferable. It will thus be seen that communication is now established between the surface and the submerged vessel at the point where it is desired to carry on the operations, and it will be realized that this can be accomplished without the use of divers and in absolute safety throughout the range or reach of the apparatus. The operators are protected by a strong steel tube, which now forms a sheltered passageway to and from the surface under normal atmospheric pressure, and no more skill is required to go down within working reach of the sunken ship than that required to go up or down a flight of stairs. It will also be seen, by referring to the sketch, that the operators are where they are protected from the currents, and even quite a severe storm on the surface would not interfere with work below, so long as the surface vessel could be held to her moorings.