The Duke of Lancaster was an ex passenger and car ferry grounded at Mostyn in 1979. It had a short lived life as a "fun ship" which ended in the early 1980s. I assume it has just been sitting there rusting away since then.
Getting on or in was impossible but I did go one further than most by getting through the fence, inside the dock and tried the doors and climbed the rusting staircases. I would love to see inside this baby
If you don't know the history there is an article HERE
Entry door, very very locked