I just found a link to this on another forum I frequent.
Shipwreck UK It's based on the
Shipwreck Index of the British Isles series by Richard and Bridget Larne, who are actively involved in the site itself. I have volume 4 of the series, which deals with Scotland and was used extensively by the Royal Commission on Ancient & Historical Monuments in Scotland when they were setting up CANMORE, the online version of the NMR for Scotland.
It's very early days for the site, but it's looking good; they have some nice info dealing with U-Boat losses around the British coast (something dear to my own heart), and in time it could develop into a great little resource.