St Catherines Deep

St Catherine's Deep is a chalk-and-clay channel scoured by tidal flow three miles off Ventnor, Isle of Wight, flanked by a ridge rising to within 15m of the surface. St Catherine's Race — among the worst tidal races in the British Isles — cuts the trench 60m+ below the seabed, so this dives only at slack water on neap tides, often under 30 minutes, boat access only. Two wrecks cluster at 38-40m: the WWI steamer Tweed (torpedoed 1918) and an unidentified stone-cargo vessel excavated by the Maritime Archaeology Trust on Trimix. Wood is gone, leaving iron and brass — cannon, anchors, a cooking pot — on gravel-over-chalk. Visibility runs 3-4m, briefly 6m near bottom. Conger eel and bull huss work the wreckage; advanced-diver terrain, tight timing required.