Before this, an event had occurred which Preble occasionally alluded to in after life, and which, marvellous as it seems, must be accepted as true, for Preble was too close an observer to have been deceived, and too sensible a man to have assumed that he saw a thing which he did not really see.

In the summer of 1779 young Preble was attached to the Protector, a smart little continental cruiser, under the command of Captain Williams, a brave and enterprising commander. The Protector was lying in one of the bays on the Maine coast, near the mouth of the Penobscot, when on a clear, still day a large serpent was seen lying motionless on the water close to the vessel. Captain Williams examined it through his spy-glass, as did every officer on the vessel. Young Preble was ordered to attack it in a twelve-oared boat, armed with a swivel. The boat was lowered, the men armed with cutlasses and boarding-pikes, and quickly pulled toward the serpent. The creature raised its head about ten feet above the surface, and then began to make off to sea. The boat followed as rapidly as the men could force it through the water, and the swivel was fired at the serpent. This had no apparent effect, except to make the creature get out of the way the faster. Preble, however, had had a complete view of it for some time, and said, in his opinion, it was from one hundred to one hundred and fifty feet long, and was about as big around as a barrel. This account must be accepted as exactly true in every particular, coming from a man like Edward Preble; and when he says he saw a sea-serpent from one hundred to one hundred and fifty feet long and as big around as a barrel and got close enough to fire at it, it must be absolutely true in every particular. It must be remembered that Preble died long before sea-serpent stories became common.[6]

Preble saw much service in the Revolution, and was the hero of a very daring achievement not long after his onslaught on the sea-serpent. He was then serving as first lieutenant on the Winthrop, a small cruiser. Captain Little, of the Winthrop, heard there was an armed brig lying at anchor under the guns of the British breastworks on the Penobscot. He gave permission to Preble to cut the brig out, if possible. It was determined to steal in upon her at night, and carry her by boarding. On a dark night, therefore, Preble, with forty men, ran in unperceived, and the Winthrop got alongside her enemy. They all wore their white shirts over their jackets, so that they could tell friends from foes when once on the British vessel. The officer of the deck of the British ship mistook the little Winthrop for a tender of their own, and called out, "Run aboard!" "I am coming aboard," answered Captain Little, as his vessel shot alongside. Preble, with only fourteen men, leaped on the brig's deck, when the Winthrop caught a puff of wind and drifted off. As they passed ahead, Captain Little called out,—

"Shall I send you some more men?"

"No," coolly answered Preble; "I have too many already."