I thought I'd pop this in this thread, rather than starting another one, as wreck enthusiasts are already here!
I was scanning through Ebay today and came across this cover. It looked so bad that I had to look at it.

Really badly listed as "UK Penny Red still on Envelope Cover", with this description:
[Khyu]lton & Wilson agents
134 Waterloo Road
Liverpool
P 4
Mrs. Hazelton
on board the
Lochmaster Castle
Docks
Liverpool
The agents name is Elkington & Wilson, so some research to do there. The name of the ship is actually "Lochmaben Castle". A quick Google, and I found out that the ship was wrecked in 1855:
"Lochmaben Castle, for Quebec, was ashore on the Bird Rocks, Gulf of St. Lawrence, 4th June. Passengers and Crew saved."
and
"WRECK OF A VERY CROWDED EMIGRANT SHIP - Accounts received at Lloyds by the American mail report the wreck of the English ship "Lochmaben Castle." Captain TURNER, with nearly 600 souls on board, on a formidable reef known as the Bird Rocks, in the gulf of St. Lawrence. She was a first-class ship of 1,600 tons, and left Liverpool on the latter end of May, for Quebec, with 537 passengers, men, women, and children, and a cargo of rice, &c. On the 14th ult., thick hazy weather set in, and she ran upon the Bird Rocks. Signals of distress were fired, and the greater part of the cargo thrown overboard."
The stamp seems to have moved, and the cover is heavily water-stained.
I'm going to love researching this one. I paid US$10.
Agree? Disagree?