I've read several of his books
, Grey Seas under, Serpents' Coil and the Boat who wouldn't float. I liked them all. After reading Grey Seas Under I ended up building a small scale model of Foundation Franklin based on the drawing in the book. One thing, its pretty hard to find any sort of info on HMS Frisky, which was her original name.
As for the details in the book, a lot of it can be cross referenced, and appears to be quite true. Ditto the info in Serpents' Coil.
The Boat who wouldn't float was just a good yarn and fun to read.