HMS Hilary and the Sea Serpent Used for Gunnery Practice

May 1917. HMS Hilary was on Northern Patrol duty with the 10th Cruiser Squadron, out in the North Atlantic. Her commanding officer was Captain F. W. Dean, RN.

It was about 9 a.m. The ship lay some seventy miles south-east of the south-east part of Iceland. The morning was "very fine and clear, the Iceland mountains in sight; flat, calm and smooth sea." Dean was called to the bridge. On the starboard quarter was a "living thing."

Its head was "in appearance black and glossy, with no protrusions such as ears, etc.; in shape, about that of a cow." A strip of whitish flesh ran between its nostrils, very like a cow's. "The top edge of the neck was just awash, and it curved to almost a semicircle as the creature moved its head as if to follow us with its eyes."

Then the fin. "The dorsal fin was a black equilateral triangle, which rose at times till the peak was estimated to be four feet above the water." Three independent estimates made on board put the neck at 20 to 28 feet. In a later account, Dean put the whole animal at about 60 feet.

What happened next set this case apart. The Hilary closed to about 1,200 yards. Her 6-pounder guns opened fire. The animal was to serve as a target for anti-submarine practice. The third round struck. It "produced at once a furious commotion, which reminded me more than anything else of a bather lying on his back in smooth water," Dean wrote. Then it was gone, with no trace remaining.

The sighting went into the ship's log. One crew member objected that such an entry brought bad luck. Three days later, on 25 May 1917, U-88 torpedoed the Hilary west of the Shetlands. Her commander was Walther Schwieger, the man who had sunk the Lusitania. The logbook for April and May 1917 went down with the ship. It was the only original record of the encounter.

Dean drew his own lesson. "If ever I found myself again at sea in command of a ship, and anything of the sort was sighted, I should leave it alone and make no entry in the log!"

The story reached the public in 1930. Dean's written statement appeared in Nature, which called it "an interesting and important piece of evidence for the existence of the creature popularly known as the sea serpent." Newspapers as far away as New Zealand reprinted it. Dean also told the tale in Herbert Strang's Annual, and the same year R. T. Gould published The Case for the Sea-Serpent.

No one has called the sighting a hoax. The debate concerns the animal. In 2010 a commenter on the Fortean Zoology blog argued for a basking shark, offering a photograph of one with its nose out of the water and a white stripe down its snout, "looking exactly like a cow's nose." The retellings also drift. One places the encounter in the North Sea. Another gives a different length.

The Hilary case sits beside HMS Daedalus in 1848 among the classic naval sightings. Trained observers. Clear weather. A calm sea. Several estimates made on the spot. Its cow-like head recalls the "merhorse" type in Bernard Heuvelmans' classification of sea serpents. And south-east of Iceland, one morning in 1917, a Royal Navy crew turned their guns on it.