Captain Campbell’s next command was the Special Service ship _Dunraven_, disguised as an armed British merchant vessel. She was zigzagging at eight knots in rough water, when a U-boat opened fire upon her at 5,000 yards. Captain Campbell ran up the white ensign, and returned the fire with a 2-½-pounder, intentionally firing short, and making terrified signals for the U-boat’s benefit. Then, as the shells fell closer, he let off a cloud of steam to indicate boiler trouble, and ordered a "panic abandon ship." The Germans now became more confident, and began to make hits; one shell exploded a depth charge on the _Dunraven’s_ poop, and blew Lieutenant Charles Bonner, D.S.C., R.N.R., out of his control station. The U-boat then ceased fire, and came past within 500 yards; but she was partly hidden by the smoke from the _Dunraven’s_ burning poop, and though Captain Campbell knew that his magazine and depth charges must explode sooner or later, he decided to trust his men and wait until the enemy gave him a better chance. The U-boat kept him waiting just too long. She was passing the _Dunraven’s_ stern, when the poop blew up, hurling the 4-inch gun and the gun’s crew into the air, and starting the "open fire" buzzers at the guns. The U-boat was hit, but not fatally, and at once submerged. Captain Campbell hastily collected his wounded, turned hoses on to the burning poop, where the magazine was still intact, and signalled to an approaching warship to keep away and deflect traffic, as his action was not yet ended. The second stage was begun by the enemy torpedoing the _Dunraven_ abaft the engine-room. Captain Campbell at once ordered a "Q abandon ship"—that is, he left his guns visible and pretended that the concealed gunners were now leaving after being detected. The ship continued to burn, and the submarine circled cautiously round, shelling her for forty minutes, then submerged again. Captain Campbell had still two torpedoes left, and both of these he fired at the submarine. One just missed her head, and the other passed two feet abaft her periscope. He had now lost his last chance of a kill, and signalled urgently for assistance, preparing at the same time for a last fight with a single gun. The American vessel _Noma_ came up immediately, followed by the _Attack_ and the _Christopher_. The U-boat was driven off, the fire extinguished, and the ship taken in tow by the _Christopher_. During the night it was found necessary to take off her crew and her wounded, and the _Dunraven_ was sunk at last by a British gunshot.