I read about this story (or so I thought) in Robert Sampson's book Deadly Excitements, Shadows and Phantoms. He talks about a story, "Mermaid", in Sea Stories magazine featuring Captain Leonidas Tripp as a mermaid impersonator and says this story is in the vein of the Jorkens stories by Lord Dunsany. Now I'm a sucker for these kind of tall tales, having gotten hooked on them after reading a similar series by P.G. Wodehouse, the Mulliner stories.
So I went looking for it and found this instead. Looks like George Allan England recycled plots, this one from 1908 becoming the new story in 1926. Now I don't know how his writing improved over the years, but this is an ok yarn. Nothing remarkable in 1908, but nothing bad either. If you have a copy of Sea Stories magazine dated November 1926, could you share the story with me so that I could compare the two and share them?
Enjoy the 1908 story, The Mermaid by George Allan England, here.