This vessel was originally launched from the yard of Edward Withy & Co., West Hartlepool in April 1886 as the Mercedes for Christie & Co., of Cardiff. She later went through various owners with names changes to Thrift, Grovedale and Torgerd until in 1924 when she was purchased by Rederi AB Iris of Stockholm, Sweden and renamed Iris, a name which she retained until her loss. Her dimensions were 275.0′ x 37.2′ x 19.2′, her net tonnage was 1182nt.
The ships to form convoy WN53 had gathered at the Tail of the Bank over the preceding 2 days, and by late evening of the 14thJuly 1941 they were all mustered. Shortly before midnight, and one by one, they dropped their moorings and began to move west towards the Cloch in single line, the Iris was sixteenth in line, and the convoy numbered twenty one vessels. The trawler crews manning the submarine boom between the Cloch and Dunoon received signals to open the net shortly after midnight, and the line of ships slipped through at three-minute intervals, each flashing their code signal as they passed.
The convoy moved south and passed Cumbrae Heads into the Firth, hugging the east coast of Arran. The weather was fair, with a light easterly breeze, visibility was around three miles. Holy Isle was passed around 03.25 and the convoy headed for the turning buoy east of Pladda where they would alter course for the North Channel.
Around 04.00 the ships entered a fog bank and visibility reduced to around 2 cables or less. The Iris reduced revolutions to take account of this, although this was generally contrary to navigation instructions for vessels travelling in convoy without a specific instruction. Around 04.20 the Iris sighted and passed the flashing light of the turning buoy and swung onto a westerly course, signalling her turn with a short blast of her whistle.
A short distance behind was the RFA Blue Ranger with her cargo of 1000 tons of fuel oil. Her master was altered by the whistle blast from the Iris, and lookouts on the bow of the Blue Ranger were alarmed to see the lights of a vessel ahead crossing their bows from port to starboard. The vessels were now very close and while both took avoiding action it did not stop the Blue Ranger crashing into the starboard side of the Iris at the stern hatch. The bows of the Blue Ranger sliced clear through the side of the Iris to the hatch cover, and it was not long before the Iris began to settle lower in the water. Within ten minutes of the collision the order to abandon ship was given and all her crew were taken aboard the Blue Ranger. The Iris eventually sank at 04.40, approximately 5 miles, 130° from Pladda Lighthouse.
The Wreck Today
The wreck of the Iris lies on a mud seabed in position 55°22.833’N, 005°00.635’W (GPS). This is one of the deeper wrecks in the area, with seabed depths of 62 metres, least depth over the wreck is around 51 metres, and an average dive depth of 55-56 metres should be anticipated. The wreck lies 090/270° with bow to west and is substantially intact although deck housings have fallen away in most areas. Visibility is generally in range 4-6 metres at best and we recommend that you dive around high water slack to take the benefit of clearer water from the North Channel on the flood tide. Note there is netting across parts of the stern of the wreck. This is an advanced dive and should only be considered by those suitably trained and equipped.