On pages 368 - 369 of In the Wake of the Sea-Serpents, Bernard Heuvelmans describes the sea serpent allegedly seen by the crew of the Tresco near Cape Hatteras in 1903. His opinion was that the story "reaches the peak of fantasy", and I have to admit that, from the summary provided, it did seem to suffer from credibility problems. Nevertheless, one always wishes to refer to the original document, which was cited as the October 1903 issue of The Wide World Magazine. Now, The Wide World was a monthly magazine in which members of the public related their own adventures in various parts of the world. It was a requirement of publication that they certify that the story was true in all particulars and, in most cases, I suspect they were. Most of them lacked the normal structure of fiction - the beginning, middle, and end - and had the air of truth about them. Just the same, there was no method of confirmation, and a number of hoaxes certainly did make their appearances in its pages.
I have been an avid fan of The Wide World ever since I was introduced to it as a boy, and have collected every edition I could lay my hands on. Regrettably, this includes only a couple before World War II. Then, a couple of months ago, a light bulb went off in my head. The Internet Archive contains a number of the early bound editions, including volume 12, where the relevant article appears on pages 147-155. I would really like to introduce you to this wonderful magazine, and I would seriously suggest that you read it. But for those who lack either the time or the inclination, I shall publish the article here.