MERCIA - Cornwall & Devon

The Mercia, a tug sunk by a mine in 1942, sits in just 4m of water, making it a fantastic, shallow dive for almost anyone. We love it because it’s a proper wreck, not just a pile of rubble, and the sheer volume of life that’s made it home is incredible. You’ll find schools of pollack hanging in the superstructure, conger eels tucked into every crevice, and the whole wreck is encrusted with plumose anemones, especially on the deeper side. Visibility here can be a bit variable, but on a good day, with the sun filtering through the shallows, the light play on the wreck is beautiful. We'd suggest timing your dive for high slack water to avoid any current and maximise your bottom time poking around the engine room and the bow. It’s perfect for extended exploration, photography, or even just a leisurely drift over the deck. Our favourite aspect is the sheer density of colour from the anemones and jewel anemones – it transforms the wreck into a vibrant, living reef.

Location
Cornwall & Devon, United Kingdom, Mediterranean & Europe
Coordinates
51.525467, -2.809917
Type
wreck
Maximum Depth
4m

Marine Protected Area: Severn Estuary

Best Time to Dive in Cornwall & Devon

The warmest water temperatures in Cornwall & Devon occur in January, averaging 9.6°C. The coolest conditions are in December at 9.6°C.

Monthly Water Temperatures

  • January: 9.6°C (air: 7.3°C)
  • February: 9.6°C (air: 8.4°C)
  • March: 9.6°C (air: 8.6°C)
  • April: 9.6°C (air: 10.1°C)
  • May: 9.6°C (air: 12.6°C)
  • June: 9.6°C (air: 15.2°C)
  • July: 9.6°C (air: 16.6°C)
  • August: 9.6°C (air: 17.1°C)
  • September: 9.6°C (air: 15.9°C)
  • October: 9.6°C (air: 13.5°C)
  • November: 9.6°C (air: 10.7°C)
  • December: 9.6°C (air: 8.7°C)

Nearby Dive Sites in Cornwall & Devon

Nearest Dive Centres to MERCIA

Marine Life in Cornwall & Devon

Home to 192 recorded species including 93 reef fish, 18 sharks & rays, 13 whales & dolphins, 11 crabs & lobsters, 11 other, 10 seagrass & algae.

Notable Species

Recommended Packing List for MERCIA

Based on average water temperature of 9.6°C.

  • Drysuit - water at 10°C demands a drysuit with thermal undergarments
  • Hood & Gloves (7mm+) - critical to prevent heat loss
  • Mask - essential for every dive
  • Fins
  • BCD - buoyancy compensator
  • Regulator - your most safety-critical piece of gear
  • Dive Computer - tracks depth, time, and NDL
  • Surface Marker Buoy (SMB) - essential for boat pickups
  • Dive Torch - useful for crevices and colour at depth
  • Underwater Camera - capture your diving memories