HMSM A7 - Cornwall & Devon

The HMSM A7 is a bit of a sombre dive, but utterly fascinating. We're talking about a wreck that's been down since 1914, a British submarine that just never came back up during an exercise off Rame Head. At 36 metres, it’s a serious dive, definitely one for experienced cold-water wreck enthusiasts who appreciate a piece of history. What hits you first, even through the murk sometimes, is the sheer scale of the thing for its time – 30 metres long, quite slender, sitting upright on the seabed. You can often make out the conning tower, the torpedo tubes, and the general shape of a submarine, even after all these years. It's not a wreck you penetrate, given its age and classification, but you can certainly swim around and over it, getting a real sense of its past. The marine life here is classic Cornwall. You'll often find conger eels peering out from gaps, their heads like gnarled tree roots. Ballan wrasse dart amongst the plates, and the wreck itself is encrusted with dead man's fingers and anemones, painting a surprisingly colourful picture on such a dark relic. We’ve found the best visibility usually comes with neap tides and a touch of calm weather, making the journey out and the dive itself much more rewarding. It’s a sobering dive, yes, but one that always leaves you thinking.

Location
Cornwall & Devon, United Kingdom, Mediterranean & Europe
Coordinates
50.308750, -4.300110
Type
wreck
Maximum Depth
36m

Marine Protected Area: Whitsand and Looe Bay

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 HMSM A7

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 HMSM A7

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