The vessel had been under tow by tug towards Ireland after a period in the south of England when it began taking on water some 10 miles west of South Stack.
Holyhead’s Severn class all-weather lifeboat Christopher Pearce was called at 2.20pm and launched immediately, arriving on scene within 40 minutes.
By that time, the 36m vessel was in trouble and beginning to sink from the bow.
The Holyhead lifeboat crew quickly ascertained that the paddle steamer did not have anyone on board, and did not contain any fuel.
A swift decision was made by Holyhead coxswain Tony Price that the situation was too dangerous to try and put any crew on board the stricken vessel.
Within half an hour, the vessel had sunk further into the sea, and at 4.20pm she sank completely into the 50m deep waters.
“It was very sad to see such a lovely vessel sink like that, but fortunately no one was endangered and the lack of fuel on board meant there were no environmental issues,” Price said.