It turns out that a number of compilation books were written by early members of the Club, though nothing quite along the lines of The Floating Admiral.
So what about these various lesser known authors? The first is Victor Lorenzo Whitechurch, who, like Ronald Knox, was a clergyman. He was also a railway enthusiast. He wrote a number of short stories, and some 24 books, some of which are still readily available. His most famous detective was Thorpe Hazell (created to be as unlike Sherlock Holmes, as possible, apparently!).
There’s not a lot about his life or history on the Net, apart from the link above, though several of his better-known books are listed.