Pen Wyn is one of many pinnacles on the Manacles Reef, sitting next to Vase Rock. The top of the rock is around 6m, with the sea bed as far away as 44m. Covered in anemones and corals, it is often described as an underwater garden. One of the U.K’s best reefs. It is so close to Vase rock that one dive could encompass both sites.
The Caroni Rivers detonated a mine previously laid by U-34 (Kplt W.Rollmann). It was built in 1928 and weighed in at a hefty 7807 tons. She was on route from FALMOUTH for sea trials, in ballast, when she hit a mine laid by U-34 and sunk. All the crew were saved.
The wreck is in three pieces, two with significant pieces left. These areas are a little distance from each other. The site is very flat after being reduced by HMS Caldy in 1949, the highest part is only a few metres from the sea bed. The two pieces are at 23m and 28m at high water. Slack water, or very close to slack water, is required to dive any of the Caroni Rivers wreck.