Kara C returns from the dive.

THEY WERE VERY ENTHUSIASTIC about the dive but asked me to keep quiet rather than publicise it, as most divers would wish for a newly discovered wreck.
Well, keeping quiet about the Drop-off is no longer an issue. The more advanced divers and sea-searchers with the local Seasearch group are busy surveying along it, with the results being entered into the national database of marine life and habitat.
The Drop-off is more than one dive site. It runs along the coast for several miles, possibly a submerged coastline from when the sea level was considerably lower. Looking at the chart, there is nothing to indicate that it is there, but it roughly follows the 30m contour.

SKIPPER RICHARD HEADS THE BIG RIB Kara-C out from Mountbatten. It seems that we have barely got going and we are already passing Bovisand and leaving Plymouth Sound by the east end of the breakwater. Two miles and under 10 minutes later, he cuts the throttle and studies the echo-sounder.
The Drop-off is no longer a secret, but the GPS numbers for its best dive spots are. We are looking for a section that hasnt been surveyed before, so the wall coming up on the sounder is a reassuring sight.
The shot goes in and the first pair of divers soon follows it, down to the top of the wall, with instructions not to pull it off the edge. Nevertheless, by the time the rest of us are ready to follow, the waves have pulled it over the edge and Richard has to re-set it.
Its an intentionally small, light shot, to minimise damage to the forests of seafans along the top of the wall.
I swim down through a little bit of surface current into a well-judged slack water below.
The angle of the shotline indicates that it is still perched at the top of the wall. Right at the edge, as it turns out, the seabed coming into view at 31m.
I push air into my drysuit to make sure I am neutrally buoyant before hitting the bottom. I dont want to squash anything inadvertently.
My buddy already has his slate out and is busy taking notes, bottom-time limits making it necessary to get everything down quickly. It reminds me of me when I am sketching a wreck - head buried in slate and notes as we work along the wall.
From previous surveys on the Drop Off, the forest of seafans extends all the way along it, making it biologically important as one of the best seafan forests in the country, especially when scallop-dredgers are busy destroying those in Lyme Bay.
Between the seafans, white colonial anemones cluster in cracks and around the fan bases. These are also of interest, because the prevalent species of colonial anemone in the South is yellow, with the white species being found further north. Are these northerners moved south, or a pale variation of the yellow species
Another feature of Drop-off marine life is the sunset cup-coral. These fairly rare species have been found on all other sites surveyed here, making it one of their key locations in British waters, but we dont find any on todays marks.
Perhaps this has something to do with the location, or perhaps the reduced visibility after several days of offshore wind. It only goes to fuel enthusiasm for further survey dives, to find out just where they start and stop.
I even find some scraps of wreckage - an iron ring, what looks like some sort of nozzle and a large plate with bolts attached. Not real wreckage, just junk dropped overboard from ships approaching Plymouth and now part of the marine environment.
Wreckage and rubbish is also recorded by Seasearch, including all the fishing line that anglers have lost tangled in the seafans. Where it can be done without harming the marine life, line is bundled up and recovered.
While the Drop-off is little dived, anglers have certainly been making the most it.
* One-day Seasearch courses cost £30-£40, weekend courses with diving £70-£90. Call Seasearch on 07776 142096 or visit www.seasearch. org.uk. In-Deep Dive Centre, 01752 405400, www.indeep.co.uk. Kara-C, 0797 4015846, www.kara-c.co.uk

Pink sea fan with white (or perhaps yellow) colonial anemones growing over it
colonial anemones up close
dead mens fingers
red fingers
A diver notes red fingers, a sea urchin and a brown sea cucumber on the wall.
Red fingers and pink seafans
gorgonian seafan, brown sea cucumber and spiny starfish
red and dead mens fingers and encrusting sponges
wreckage probably dropped from a ship
pink sea fans
Loading the RIB at the Mountbatten Centre