The iron paddlesteamer Princess Louise was launched from the yard of Tod & McGregor (Yard No 152) at Meadowside in Glasgow on 7th May 1872. Built for the Larne & Stranraer Steam Boat Company of Belfast she measured 211.4′ x 24.1′ x 12.4′ and her tonnage was 539 gross tons, of 187 net tons. She was powered by a compound steam engine by Tod and McGregor, Glasgow delivering 200 nominal horse power. In 1890 she was purchased by David MacBrayne Ltd., Glasgow and renamed Islay III.
She ran aground on Sheep Island, Islay at two o’clock in the morning of 15th July, 1902. She had been at the end of her regular, twice weekly journey from Glasgow to Port Ellen and was newly under the command of Captain Cameron. They had encountered dense fog as she approached Islay and she ran aground on a reef near this low lying island which is less than half a mile from Port Ellen harbour.
Interestingly this was the second time in five months that the ship had run aground. Although she was lying with a severe list to starboard she remained firm on the rock allowing all the passengers to be transferred safely, by boat, to the shore on the Ard. The cargo was also quickly removed before the ship became a total wreck.
The wreck lies in position 55°37.183’N, 006°11.066’W (GPS) on the south side of Sheep Island, or Eilean nan Caorach to give it the Gaelic name shown on most charts of the area. The actual site is close to a reef which only just breaks the surface at low tide lying 200 metres south of the shore of Sheep Island. The main items of wreckage remaining visible are her two massive boilers lying in 12 metres at the base off the reef. The seabed around the boilers is strewn with metal ribs and plates and the remains of one of the paddle wheels but clearly the wreck has been heavily salvaged.
The wreckage of the bow lies on the top of the reef in less than 3 metres and the deepest parts of the remains are around 14 metres. The site is exposed from the south but, apart from the possibility of some swell close to the reef when the wind is from this direction, the site is fairly sheltered and is free from tidal movement.