@farmerman,
I'm not sure off-hand when Tirpitz was painted but I know there is an obvious difference between his early paintings and his later ones which definitely improved with age and experience.
Regarding cover art, besides Douglas Reeman's "Kent" series, it seems he did quite a lot of dj's, many of which we are still discovering ourselves. I believe he did Mowat's "Grey Seas Under" and "The Serpents Coil", if you Google these book titles using 'images', you will see pictures of the book covers. Also he appears to have done some covers for books by John Harris, "Silent Marauders" by Graeme Cook and "Gold from Crete" by C.S Forester amongst many others..... of which we have a large number. Looking at the paintings individually, it is very apparent which ones were painted for the purpose to accomodate wraparound and titles, etc. but I will try to find out for you if any of his cover art was rejected.
Re. the website, unfortunately no idea of timescale yet, spare time is the main factor really but we would welcome any input you can contribute.
This picture of the Titanic is also one of my Grandpa's and one of my fave's.
http://www.shipsahoy.com/dml237.gif