The Manacles Reef is a huge reef with many underwater pinnacles. At high water there are a handful of rocks that break the surface, at low water many more appear. It has been the end for many ships, as many as fifty have come to grief around the Manacles. Wrecks include the Mohegan, Spyridion Vagliano, Lady Dalhousie & HMS Primrose. Pinnacles like Raglans, Vase & PenWyn are covered in life on their near vertical walls. Depths range from 6m to 44m on the reefs with wrecks at a maximum of about 28m.
As of 12th December 2013, the Manacles has become a Marine Conservation Zone.