The offensive feature of the design consisted first of a vertical spike attached to the top of the observer’s dome. In the spike was an eye through which passed a cord leading through a stuffing box to a winding spool in the forward end of the boat. The second part was a torpedo attached to the other end of the cord. In action the Nautilus would be placed directly beneath the hull of an enemy vessel, the spike being in contact with the bottom planking. As one end of the spike projected into the observer’s dome, a blow on that end would drive the upper end, which was sharp and detachable, into the ship’s timbers. Then the Nautilus was to move forward leaving the spike sticking in the ship. As she moved forward, the torpedo would trail behind, but as the cord passed through the eye in the spike, the torpedo would soon be brought into contact with the hull, when the shock would fire the discharge. In the meanwhile, enough cord would have been paid out to permit the Nautilus to have attained a safe distance.
The Commission to whom the design was submitted found in its favor, except as to the sail arrangement, which they pointed out had the larger part of its area too far aloft, and that consequently the boat would lack stability under a strong wind. A translation of the Commission’s conclusion is as follows:
The Minister of the Marine and Colonies is therefore requested to give to Citizen Fulton the authorization and necessary means to construct the machine of which he has submitted a model. There is no doubt that with the same wisdom that has been put into its conception, and the refinement and solidity of the various mechanisms comprising the whole, that he who has supervised the execution of this interesting model will be able to construct the full sized machine in a manner equally ingenious and that the new ideas that he will have obtained from study and experience will but lead to its perfecting.
Though the design of the Nautilus fell far short of that of a modern submarine, nevertheless, it was so far ahead of anything previously accomplished or suggested that it entitles Fulton to be credited with being the first to propose a type of vessel capable of plunging and being navigated beneath the surface of the water. That his plans gave promise of this accomplishment was recognized by the examining commission in their report, a report that gave Fulton great encouragement for further action. Delpeuch in his book on submarines states that in consequence of this favorable official approval: