Land Rover launching the RIB at Porthclais.

MENTION BELL ROCK, and chances are you will think of the reef guarding the approaches to the Forth and Tay off Scotland - the reef made famous by the granite lighthouse built by Robert Stevenson, completed in 1811 and still standing against all the sea can throw at it.
If that is the Bell Rock you are thinking of, then Im sorry to disappoint you.
A less well-known, though possibly even more lethal, Bell Rock marks the northern extent of the Bishops & Clerks off St Davids Head in Pembrokeshire.
While the Scottish Bell Rock has its very own lighthouse, the nearest lighthouse to the Welsh Bell Rock is three and a half miles away at the South Bishop. A picket fence of rocks and reefs fills the gap between the South Bishop and Bell Rock, backed by Ramsey Island and all exposed to the storms of the Atlantic and swept by the aggressive tides of the Pembrokeshire headlands.
The northernmost rock that stands clear of the sea is the sizeable North Bishop, and Bell Rock is a few hundred metres off the end, not quite drying at low water, just shallow enough to rip the bottom from an unfortunate ship.
Stories of wreckings recall last-minute sightings of the North Bishop, a desperate turn of the helm, moments to think the ship could escape, then a screech and a crunch as Bell Rock took its toll.
Getting there presents a difficult decision. The weather is marginal from the north-west, perhaps improving, perhaps not. We could go for the long but comfortable journey in the hardboat from Fishguard, or we could launch the RIBs somewhere closer.
With this in mind, there is still a decision to make - whether to launch from the small harbour at Porthgain on the north coast, or along the inlet at Porthclais to the south of St Davids.
In the end, we opt for Porthclais. More of the ride will be sheltered from the weather, first by the mainland, and then as we journey up Ramsey Sound.
If the weather does get worse, there are better options for plan B.
The gaps between showers of rain are getting longer. While the sun isnt out, the clouds are looking brighter and the sea doesnt look quite as angry. We have to be careful that we are not misled, however, because the tide is running with the sea, but will be against the sea on our return.
Popping out of the north end of Ramsey Sound, we pause to consider. Its not too bad, so we may as well do a few miles more and have a look.
Floating dead on the GPS numbers we cant actually see Bell Rock below us, but we can see the sea swirling over and around it. It shows beautifully on the echo-sounder. The shot goes over with plenty of time to spare for a quick investigation of the lunch supplies.
The buoy is still showing a wake as I roll over but, with a short slack water, some of us need to go in early so that everyone can have a turn to dive.
The top of the rock is a long jagged ridge, only a few metres down. As I haul along the line it looks promising, with a few scraps of wreckage wedged into the tight valleys.
With instructions that the way to find the main body of the wreck of the Langton Grange is to carry on over the ridge and round to the right, I descend to 20m and set off on a course that should intersect with wreckage.
Rocks on the way are carpeted in a mixture of furry hydroids and vibrant jewel anemones. Cracks contain crustaceans appropriate to their size, from shrimps to lobsters.

FIFTEEN MINUTES INTO THE DIVE, and I am beginning to think that something has gone wrong. At 5852 tons, the Langton Grange is a pretty big wreck to find on a small rock. I was expecting to see wreckage by this point.
I drop 10m deeper and loop back. On the way, I pass other divers who entered before me. They have been deeper without result, including one diver who has dived here several times before.
I shrug and point to where I have been. They shrug in turn, and point to where they have been.
Back past my starting point, I begin a loop in the other direction. Above me on the ridge, I can just pick out the silhouettes of other divers returning to the surface.
Having established that the problem was not one of overshooting the wreck at the start, I head back up the ridge to shallower water. A crevice in the rock widens to a small cave, just a little too small for me to fit into comfortably.
Having passed scraps of wreckage at the top of the ridge, and with no more sign of wreckage on this side, my reasoning is that perhaps there is something on the other side.
My reasoning pays off within a few metres of crossing the ridge. I am on the well-splattered wreckage from an obviously substantial steel wreck.
The diameter of the masts and the size of the winches suggests a vessel of a few thousand tons. But is it the Langton Grange Could it instead be the 1923 wreck of the 3444 ton Cymric Prince
I am not into decompression yet, so continue down the wreck. My original impression of size remains, but the trouble is, among all the masts and winches, I can find no sign of boilers, engine or propeller shaft.
There are stories of steel-hulled sailing ships having been wrecked on Bell Rock, but lack of identification and inconsistent information make it hard to pin these down. Besides, the wreckage is just too heavy-duty for a sailing ship.
By the time I head back up the rock again the current is running, more so the shallower I get. By the time I am clinging onto the shallower part of the wreckage,
I know that there is no way I can do a drifting decompression without passing through a washing machine.
I find a crack at 6m and wedge myself in for 10 minutes, plus an extra five minutes as I expect the final part of my ascent will be a little hairy.
Its not the upcurrents on the leading edge of the rock that worry me. With strong upcurrents come equally strong downcurrents.
I expect a DSMB would head off at a weird angle, then either drag me down with it, or I would drag it down with me. Either outcome is not to be relished. I consider taking a picture or two, but I just dont have enough hands.
I let the camera trail on its leash while getting my self-inflating delayed SMB ready, and clawing another metre or so up the rock. I manage to set the delayed SMB off, hit the inflate button on my suit and let go of the rock so rapidly that I am not sure which happened first.
It seems to work. I drop only a couple of metres before a tight line and my over-buoyancy halt the descent, then I find myself rapidly dumping air as I run through another pocket of upcurrent.

NOW FURTHER AWAY from the focus of it all, the washing machine is more manageable, and I even make a few minutes at 3m before taking my time over the last short ascent of my line.
The RIBs have already picked up the second wave of divers. They had all kept their dives shorter and missed the spin cycle.
We take the scenic route back to Porthclais, round the outside of Ramsey and through the canyon and rapids at Twll y Dillyn.
As we cross the southern end of Ramsey Sound, the sun is out.
So which wreck was it Without machinery, it certainly wasnt the Langton Grange some of the others had dived before. The last pair in found it; I just hadnt gone far enough along and round the ridge in the first place. The shot must have caught further back along the ridge than originally thought.
Looking at original photographs of the Langton Grange and Cymric Prince, the latter just doesnt have enough masts, while the Langton Grange had many pairs of dual-purpose short ventilator/mast structures with derricks arrayed along the holds. This would certainly fit in with the heavily built but short tubular masts I encountered.
Volume 1 of Tom Bennetts book Shipwrecks Around Wales and Volume 5 of Richard Larns Shipwreck Index give the answer.
On 5 August, 1909, the Langton Grange had driven across Bell Rock and two days later its back had broken, so it lies in two parts across the rock. I had been diving the bow section.

Mark Deane at the helm.
John Liddiard beneath ribs and hull plates on the mystery wreck.
Spider crab on a spar on the wreck.
Ribs and hull plates on the Cymric Prince or Langton Grange
a hull rib
anchor winch.
Running the rapids at Twll y Dillyn by Ynys Cantwr.
GETTING THERE: Follow the M4 and A40 to Fishguard and on to Goodwick (where the ferry terminal is). Celtic Diving is by the public slip at Ocean Lab.
DIVING & AIR: Celtic Diving, Mark Deane, 01348 874752,
ACCOMMODATION: There are four-bed bunk-rooms for up to 20 people at Celtic Diving.
LAUNCHING: A good 4x4 can launch along the inlet at Porthclais, to the south of St Davids. On the north coast, the harbour at Porthgain has a slip that can be used at any state of the tide. At Goodwick the slip dries for a couple of hours either side of low tide.
TIDES: Slack water is vital and occurs three hours after high and low water Milford Haven.
FURTHER INFORMATION: Admiralty Chart 1482, Plans on the South and West Coasts of Dyfed. Ordnance Survey Map 157, St Davids and Haverfordwest Area. Shipwreck Index Volume 5, West Coast and Wales, by Richard Larn. Shipwrecks Around Wales Volume 1 by Tom Bennett. Fishguard tourist information, 01348 872037.