My first sign of the Seven Stones is the lightship, anchored between the reef and the northbound shipping channel, slightly to the north of our course. I am struck with the thought that the Seven Stones has only ever had a lightship and no-one has ever tried to build a lighthouse on the reef. The lightship is now automatic, but in years past the lightship crew had featured in many tales of rescue and providing refuge for shipwrecked mariners.
The only large scale chart of the reef is in fathoms based on a survey by Captain G Williams in 1863. Divers from Penzance have been plotting their own marks for the rocks using differential GPS, showing positions that varied by a few hundred metres from many of the charted locations of the rocks. The shape of the reef was recognisable but skewed. A good reason to be there at low water spring tide when the rocks are showing. In 1863 Captain Williams must have done very well to even get that accurate from this far offshore with little in the way of landmarks to triangulate from.
Our final choice is dictated by the sea conditions as we arrive at the Seven Stones. We settle for diving a breaking rock at the northern extent of a group marked as the North-East Rocks on the chart. Water to the north of this rock is generously deep enough to approach the rock and drop divers almost on top of the remains of the 2,681-ton factory trawler Rarau.
The Rarau was built in 1972 in the Polish shipyard of Gdansk and operating with a Rumanian crew. On 29 September 1976 the Rarau drove straight onto the rocks in fog. All 84 of the crew were rescued and put ashore in Falmouth, then a week later the Rarau slipped into deeper water and sank.
I descend almost on top of a twisted hull plate, lying by itself at a cross-road of canyons in the granite. The straight on path looks more interesting and we follow it to deeper water.
We wind our way north-west, then circle back to the east, following some truly spectacular walls of colour. In water this clear it is little surprise that even at 25 metres there are sizeable sprigs of kelp on the horizontal faces of the rock. As usual for Cornish reefs, the vertical surfaces are a dense cluster of jewel anemones and hydroids, with tightly packed plumose anemones on the more exposed corners.
I pass odd scraps of wreckage, but nothing significant. It is half hour into the dive before we come across the main body of the wreck. By that I dont mean intact, but an area of wreckage with the occasional rock, rather than rock with the occasional wreckage.
I follow the line of the wreck from the engine to the stern, across a jumble of plates and girders, past a large trawl winch with steel cable now rusted to the drum and sections of propeller shaft.
One large intact item I am unable to identify - a cylinder getting on for 2.5 metres in diameter and 5 metres long, a maze of tubing on the outside, with a spherical cap at one end and a spherical indentation at the other end. In another context I would have thought Soyuz capsule.
Forwards of the engine a wall of rock builds on the left and soon we are in a wide gully. The wreckage fizzles out a bit and then we encounter a familiar bent plate. We are back at the crossroads where we started the dive. Continuing straight across is the much smaller bow section of the Rarau. We had begun the dive by swimming straight through the middle of the wreck!
Our decision to dive the Rarau had been pretty much dictated by sea conditions. The Seven Stones have claimed an estimated 200 ships over the years. Further up amongst the North-East Rocks are the remains of the 1,200 ton steamship Chiswick which ran aground in 1891. The captain is reported to have ordered every man for himself before electing to go down with his ship.
Beneath the Flemish Ledges at the south end of the reef are the remains of the Fantee, a diesel driven 6,300 ton cargo ship which struck the reef in fog in 1949. Hardwood from the cargo was still being salvaged as recently as 1992.
The most notorious wreck on the Seven Stones is the 61,000 ton super tanker Torrey Canyon. On 18 March 1967 the Torrey Canyon was en-route to Milford Haven and should have been in the northward shipping channel between the Seven Stones and Lands End, but a few miles off course she drove straight over Pollard Rock at the north-east side of the reef. The impact knocked the top off Pollard Rock, so perhaps the reef should be re-named Six Stones.