On the 3rd of April at the Isle of Man, I photographed a large passenger ship (cruise ship, cruise ferry, or RO/RO ferry), maybe 10–20 km off the west coast:
The vessel was moving slowly in southerly direction. It looks like it's either a cruise ship, or a very large (RO-RO) ferry with all cars in the hold; but considering time and location it would have to be on the Belfast–Liverpool route and their ferries on that route (MS Stena Lagan and MS Stena Mersey) are much smaller, and it lacks the characteristic S for Stena. It's a bit small for a cruise ship. If it was in Norway I'd say it's one of Hurtigrutens ships, but this is the Irish Sea…
Unfortunately, the lens I was using was not strong enough te resolve the lettering on the vessel.
My camera was located at Corrins Hill just south of Peel, Isle of Man. I was looking north-north-west, back along the coast. So I would expect the ship to have been located somewhere northwest, or perhaps straight north of Peel.
What vessel did I spot? How would I determine it?