As the crabs approached, the stern-jacket of the Adamant was let down, and the engines were slowed. This stern-jacket, when protecting the rudder and propellers, looked very much like the cowcatcher of a locomotive, and was capable of being put to a somewhat similar use. It was the intention of the captain of the Adamant, should the crabs attempt to attach themselves to his stern, to suddenly put on all steam, reverse his engines, and back upon them, the stern-jacket answering as a ram. The commander of the Adamant had no doubt that in this way he could run into a crab, roll it over in the water, and when it was lying bottom upward, like a floating cask, he could move his ship to a distance, and make a target of it. So desirous was this brave and somewhat facetious captain to try his new plan upon a crab, that he forebore to fire upon the two vessels of that class which were approaching him. Some of his guns were so mounted that their muzzles could be greatly depressed, and aimed at an object in the water not far from the ship. But these were not discharged, and, indeed, the crabs, which were new ones of unusual swiftness, were alongside the Adamant in an incredibly short time, and out of the range of these guns. Crab J was on the starboard side of the Adamant, Crab K was on the port side, and, simultaneously, the two laid hold of her. But they were not directly astern of the great vessel. Each had its nippers fastened to one side of the stern-jacket, near the hinge-like bolts which held it to the vessel, and on which it was raised and lowered. In a moment the Adamant began to steam backward; but the only effect of this motion, which soon became rapid, was to swing the crabs around against her sides, and carry them with her. As the vessels were thus moving the great pincers of the crabs were twisted with tremendous force, the stern-jacket on one side was broken from its bolt, and on the other the bolt itself was drawn out of the side of the vessel. The nippers then opened, and the stern-jacket fell from their grasp into the sea, snapping in its fall the chain by which it had been raised and lowered. This disaster occurred so quickly that few persons on board the Adamant knew what had happened. But the captain, who had seen everything, gave instant orders to go ahead at full speed. The first thing to be done was to get at a distance from those crabs, keep well away from them, and pound them to pieces with his heavy guns.