IF I WAS TO USE THE WORD UNDISCOVERED TO DESCRIBE THE RUNNEL STONE, you might think I was being economic with the truth. Yet this site is undiscovered in the sense that most divers think of the Runnel Stone as the being the wreck of the City of Westminster (Wreck Tour, June 1999), rather than the much larger area of reef that stretches between the stone itself and Gwennap Head.
Sure, local divers and some visiting clubs which have spent time getting to know the area are familiar with the place, but for most visiting divers who get away from the Runnel Stone and the City, the rest of this reef really is unknown territory.
There are so many opportunities to dive ridges and pinnacles in the underlying granite reef, to locate barely dived wreckage and to drift across the reef, that there is more than enough to keep you occupied for a long weekends diving - if not an entire weeks, providing the weather obliges.
The Runnel Stone itself is easy to find. There is a bell buoy just 100 metres further offshore than the wreck and two cones to line up on the cliff tops above Gwennap Head.
From the buoy, follow this line in until the pinnacle shows on the echo-sounder. I like to drop a shot just to the west of this line so that it drags back and hooks across the rock.
You have to be careful above the Runnel Stone in any boat. Even in an apparently flat-calm sea, the groundswell can build to a breaking wave as it crosses the rock, and flip you over. Its prudent simply to sit and watch the area for a few minutes to check the conditions before closing in with echo-sounder and shotline at the ready.
The remains of the bow half of the 6000 ton City of Westminster lie immediately to the west of the stone, with the remains of several other wrecks scattered immediately around the rock. The stern half lies further offshore in 50m.
About 100m east of the Runnel Stone is Lee Mean. The two are separated by a 25m-deep valley, the bottom of which is filled with small anemone-covered rocks and sparsely scattered bits of wreckage.
Lee Mean runs roughly east-west. To the south it drops steeply to a depth of just short of 30m, then breaks onto a sandy slope. To the north there is a shelving rocky slope to 20m or so.
As on the Runnel Stone, everything is covered in squidge, with kelp firmly rooted to all but the vertical faces.
It was while decompressing on the north side of Lee Mean that I noticed a small sunfish circling me. Alas, my film had been spent long before and I missed the opportunity to capture an image of this rare visitor.
Three hundred metres to the north-east of the Runnel Stone, an un-named rock rises to 9m from the edge of the reef at 15m. The reef slopes down to 25m or so, but it is in the shallower water just to the north of this rock that the remains of the 1800 ton ore ship Febrero lies, having gone down with all hands except the ships cook in 1910.
The stern of the Febrero must have come to rest on this rock, as the propshaft sticks out to the south through a gully that splits the rock into two pinnacles. The wreckage is flattened, with plates and girders surrounded by a sprinkling of iron ore cargo, but the outline of the wreck is easily distinguishable, with bows to the north and boilers moderately intact.
Another 300m to the north is Lee Ore, an area of rocks rising from 10m to just 2m on the chart. Perhaps the name comes from the cargo of the Febrero, or perhaps it has some other derivation from an ancient Cornish term.
In water this clear and shallow, the kelp is big and dense. The trick is not to swim above the kelp, but to streamline your equipment to a minimum and go exploring the jungle and gullies between the roots. It can make a nice second dive, but is a bit of a waste of a precious slack water while there are more dramatic pinnacles and wrecks nearby.
The 1600 ton steamship Lake Grafton struck Lee Ore in 1920, then floated off to the south, with the bows touching the bows of the Febrero and the stern towards the west.
After the anchors and winch at the bows, it is difficult to make out the rest of the Lake Grafton, because the 1850 ton Joshua Nicholson came to rest on top of it in 1917.
This is a unique wreck in that the ship was originally torpedoed by U-70, then taken in tow before breaking loose and striking Lee Ore.
Most divers refer to this wreck simply as the Munition Ship, because of the piles of shells that are to be seen among the holds. To locate this wreck from a boat, come in on a line to the right of the cones that mark the transit for the Runnel Stone, so that the base of the cones just touch. The boilers rise 3 or 4m from a mostly flat seabed at 12-14m.
Just to confuse things, there is a shallow ridge rising to 9 or 10m just south of the wreck.
Once you know the area well, it is possible to make a fast swim round all these wrecks in one dive, beginning with the City of Westminster and the Moorview on the Runnel Stone, then following the edge of the reef to the north-east to the stern of the Febrero, then off the bows of the Febrero to the Lake Grafton and the Munition Ship.
For a deeper dive and back on spectacular rocks, 500m west of south-west from the Runnel Stone is a rock marked Poldew on the chart, rising to a depth of 7m.
This is an easy dive at slack water, but the last time I dived here was on westward current as part of a drift. Having found the shallow point with an echo-sounder, we tracked the 20m contour back along the edge of the reef about 200m to the east and rolled in.
The seabed was white granite sand and rocky ledges with the usual covering of anemones and sprigs of kelp, easily able to grow this deep in the clear water.
The current was not overwhelming and we drifted along gently, finning a little to the north to maintain our course.
After five minutes or so we neared Poldew, and the current picked up and started to become more turbulent. Out of the distant haze a dark shadow appeared - an enormous square block of granite as big as a house.
We swam hard cross-current to prevent the SMB line that led us from fouling on the top of the rock, then equally hard back in behind the rock as the seabed dropped away.
The SMB line was tugging aggressively in the surface current, but we were now tucked in to a slack area behind the rock and, SMB permitting, could stay there.
All surfaces were covered in densely packed anemones and hydroids. Wrasse and pollack were everywhere. It was starting to become a bit of a clichŽ.
From here we followed the sheltered side of the rock northwards, crossing small breaks with current steaming through. To surface, we drifted away from the rock to follow our SMB line up in less turbulent water.
From a boat-handling point of view, you really need two boats to cover this dive, one to stay with the divers that manage to duck in behind the rock, and one to follow those who miss it and carry on drifting. You also need a GPS to maintain position should an SMB drag under while divers are hiding behind the rock.
On an eastward current it is possible to make a similar dive to drift across and behind the Runnel Stone and Lee Mean, though it is much easier to snag an SMB line and can be risky for a boat above the Runnel Stone itself.
I would recommend that all divers also carry a delayed SMB, ready to make an immediate ascent should the main SMB line snag and break.
For an easier second dive at most states of the tide, there are many opportunities for shallow forays just off the cliffs between Gwennap Head and Porthgwarra.
Terrain varies from flat rocky reef with kelp to rock gardens of enormous boulders with narrow canyons in-between. I wouldnt sacrifice a chance at the sites further offshore for a dive under the cliffs, but they still make a good dive if tides or weather force you inshore.
To get the most out of a long weekend on the Runnel Stone, it is vital to plan with the tides in mind.
Slack water is reliably one hour before high water Penzance and that is the only slack on which you can count. On neap tides its usually slack enough to dive an hour before this and up to an hour after.
Sometimes its also slack two hours after high water Penzance, but thats a bonus and should not be relied on.
The best weekends to pick are those when high water Penzance falls at about mid-day, giving reliable slack water for a first dive. This can be followed by the possibility of the less predictable slack water after a short surface interval, a drift after a longer surface interval, or coming in close to shelter below Gwennap Head for the second dive.
Beware: if you pick the wrong weekend for tides, there could be no slack water at all at a time of day acceptable to most divers. Also note that I have referred to eastward and westward currents rather than flood and ebb tides. One look at the tidal stream atlas will show that the concept of flood and ebb is rather mixed up in this area!

Anemones include many-coloured varieties of Sagitaria elegans and Actinothoe sphyroeta
The Runnel Stone is all about big granite scenery covered in anemones and hydroids
Launching at Porthgwarra is feasible only with inflatables and a lot of hard work to carry them by hand
John Liddiard gets up close to those hydroids
jewel anemones


GETTING THEREM5 to Exeter, then A30 to Penzance..

DIVING & AIR: Bill Bowen runs the hard boat Son Calou from Penzance harbour and has a compressor on the pier (01736 752135). Local centres include Porthkerris Cove Diver Resort (01326 280620) and Undersea Adventures (01736 333040).

LAUNCHING:The slip in Penzance harbour is wet for most of the tide. A slip at Lamorna Cove is wet for a couple of hours either side of high tide and leads to a soft sandy beach. There is a slip at Sennen next to the lifeboat station, but the area can be very crowded with surfers and tourists doing Lands End. It is also possible to launch across the beach at Sennen, but beware of soft sand, heavy surf and shallow reefs. Harbour fees are payable at all these slips. Closest to the Runnel Stone is Porthgwarra, where launching is just about practical for a hand-carried inflatable, but nothing bigger or heavier. For club RIBs Porthgwarra can be a nice place to stage a car with spare cylinders and stop for pasties, but please check with the Harbourmaster first, as the beach is small and can be crowded with bathers.

ACCOMMODATION:There are many campsites and static caravan sites. Moving up, there is a wide range of B&Bs and hotels in the area. Contact Penzance Tourist Information for a list (01736 362207).

QUALIFICATIONS:This is a excellent location for a club trip, with easy but spectacular dives for new sports divers through to dives that will challenge the abilities of the most experienced.

FOR NON-DIVERS In addition to some excellent beaches ranging from busy Sennen to quiet little coves, there are some nice coastal walks with views of the offshore rocks, including the Runnel Stone. Whales can sometimes be seen from the cliffs at Gwennap Head. The obvious tourist site is Lands End. If you dont want to pay to do the theme park, the coast path has a right of way past it along the cliff top. There are many other tourist attractions in this part of Cornwall.

FURTHER INFORMATION Admiralty Chart 2345, Plans in South-west Cornwall. Admiralty Chart 777, Lands End to Falmouth. Admiralty Publication NP250, Tidal Stream Atlas, The English and Bristol Channels. Ordnance Survey Map 203, Lands End, The Lizard and The Isles of Scilly. Diver Guide - Dive South Cornwall by Richard Larn. On the web try www.cornwall-online.co.uk/westcorn/penzance.htm and Penzance BSAC at www.penzancediver.org