Gareth and others,just got home and made sure that Dudley Pope's The Black Ship was the right book. It's in my hands as I write and it's about the Hermione, not the SS's naval arm during the 1940s.
I've been trying to find a copy of the actual lyrics to "The Colours." It's been a while since I heard the song (I have the 12 inch single, believe it or not!). But based on my memories, I don't see how it could be based on the Hermione or the Nore/Spithead events.