WHILE THERE ARE GOOD TRANSITS for south Cornwalls Raglan reef, a pinnacle that rises to 6m and marks the easternmost extent of the Manacles, I still like to watch the echo-sounder as I drive one of our club boats out from the Voices on the main reef.
I see the reassuring drop of the reef, then a few humps, and finally the rise of the Raglan about 400m out from the Voices. It gives me an impulsive idea.
I wonder what the seabed really looks like, or more specifically, could I dive from one to the other
I begin by thinking of it as Voices to Raglan via the wreck of the Mohegan, but soon change my mind, because the other direction makes more sense.
Raglan reef is a small target heading offshore from the Voices. The Mohegan is quite a large and easily recognised wreck heading inshore from the Raglan, and from the Mohegan the route to the Voices is one I know well (Wreck Tour 8).
On balance, its a plan far more likely to succeed, and therefore one that is much safer. Starting on a low-water slack, it also has the advantage of giving me the following current of the flood-tide later in the dive.
As the next days dive rota is being sorted out, I line up a buddy who is exceptionally good on air, and put my request in with the dive marshal.
The others will be diving on the Mohegan, so it shouldnt be a problem to drop me on the Raglan first, then both boats will be waiting for divers to surface between the Mohegan and the Voices.

ALAS, THE BEST-LAID SCHEMES of mice and divers. Next day, as the boats pass the Voices, I ask our dive marshal what time slack water is. After driving one of the boats the previous day I already have a general idea, but would like to know more specifically, as she has checked the tide tables.
I am immediately terrified when she relates it as being an hour after low water Dover. Dover Why Dover Well, thats what you wrote in DIVER, she says.
I now have two sources of terror. Will we hit slack water is the immediate concern, and Could I have published that sort of ridiculous mistake in this venerable magazine is a longer-lasting concern.
I check with our dive marshal again Are you sure I usually give slack relative to Falmouth or Coverack.
She has a dizzy moment. Coverack, that was it, she replies. I thought there was something wrong with Dover.
That sorts out one of my terrors but, try as I might, I cant pin her down on which table she actually used to get the time of low, and hence slack, water.
Never mind, it feels about right, and the current doesnt look too strong.
One of the other divers jumps into the water as a human buoy to see how fast he moves relative to the transits and a nearby pot marker. This is far more accurate than watching from a small boat, because he isnt pushed by the wind as the boat is.
Finally, good news. The current is slacking at the time predicted by our dive marshal. How much anguish I could have saved myself if I hadnt asked her, and had simply waited for the appointed time! Ignorance is bliss.

WE DROP A SHOT ON THE RAGLAN, and my buddy and I are soon pulling down to the rock against the last dregs of the ebbing tide.
I send the shot up, and listen to the boat patrolling overhead. It will be waiting for five minutes in case we decide to abort, then heading in to the Voices to drop the rest of the divers before patrolling back and forth.
As usual, marine life on the sheer sides of the Raglan is magnificent, with tightly packed plumose and elegant anemones interspersed with clumps of hydroids. I work to the shoreward corner, hiding just out of the south-east-flowing current while descending beneath the resident shoal of pollack.
The sessile marine life gradually changes to jewel anemones and dead mens fingers. Finally, we meet a seabed of coarse sand beneath small rocks at 25m. A compass bearing taken from the surface gives a rough direction of travel, across and slightly into the light current.
Having said this, my plan is more to head shoreward and north without going too deep, then to follow the north edge of the main Manacles reef in to the Mohegan.
We soon come to a big overhanging block of granite, again covered in jewel anemones, the first outcrop of a kind of baby Raglan that never quite made it up to the shallower water.
At a guess it rises to 15m, though I dont leave the seabed to find out.
The current is now just about slack. After using it to navigate, I find myself missing it now, and resort to looking at my compass more often.
The seabed slowly shallows, and becomes more rocky. Occasional gorgonian seafans now stand above the ever-present jewel anemones. Urchins graze, and spider-crabs celebrate spring.
The seafans provide further navigational clues, spreading across the usual line of the current.
The rocks shallow to 20m, then give way to another plain of coarse sand with small rocks scattered. Dead mens fingers grow bigger and more lush. Jewel anemones become smaller and fainter.

WE ARRIVE AT ANOTHER GRANITE WALL. Could this be the end of the main reef, or simply another isolated outcrop
The current is now picking up from behind us, urging us on.
My intuition claims that we must have covered about half of the 400m distance. My dive computer says 25 minutes have elapsed. We could have swum faster, but have been taking the time to enjoy the dive. My buddy still has 140 bar in a 10 litre cylinder. If I were that good on air, I wouldnt be using a rebreather.
The wall of granite turns out to be another outcrop, as the seabed slopes upward and the coarse sand and smaller rocks take over the wall.
A plain of small jagged rocks like scree stretches to the 10m limit of visibility. In among the dead mens fingers and gorgonian fans, a few ross corals mark the change of scenery.
I bias our course more to the north, to make sure of hitting the northern edge of the main reef, rather than an unrecognisable part of the top of it.
The seabed gets a little deeper, and we are now back above coarse sand and scattered rocks. Yet another wall of granite with jewel anemones looms before us, and we follow as it curves north, then a little to the east.
Another wall appears on the right, and we are in a canyon, the now flooding tide helping us to fly gently through it.

THE CANYON SHALLOWS and spreads out to another jagged plain, but the encouraging signs are occasional small scraps of wreckage. Theres a section
of railing, then a section of angled rib.
The nature of the seabed changes again, with a rounded sloping reef to our left, and rounded boulders of varying size scattered below.
We drop over a ridge, and the flattened ribs and plates of the bow of the Mohegan are before me.
I wave hello to another pair of divers exploring the wreck, working my way back towards the boilers. Here, I have a moment of indecision. Should I follow the wreckage aft or do some of the swim-throughs and caves on the reef above Both routes lead back to the Voices.
In the end, my buddy tips the decision. At 50 minutes, her air is down to 80 bar.
I opt for the easiest and most direct route to finish the dive - along and across the wreck, up the boulder slope and past overhanging rocks to the northern wall of the Outer Voice.
Our final destination is instantly recognisable. A chimney of incredibly dense anemones and hydroids rises from 10m to the surface, an ideal place to stay out of the current and make a few minutes safety stop. Our boat is waiting just off the rock.

THE MOHEGAN
On 14 October, 1898, the 6889-ton passenger liner Mohegan was on her way from London to New York when navigational error led her directly towards the east coast of Cornwalls Lizard Peninsula, and the notorious Manacles.
The coastguard fired warning rockets, and the Mohegan turned hard to port. Now inside the area of the reef, this was the worst thing the captain could do.
The rudder was torn off on the submerged Vase rock. At the mercy of the wind and current, the vessel wallowed on half a mile south before striking sideways into the Voices reef. The engine-room flooded and all lights went out.
In the darkness and confusion, only two of the Mohegans eight lifeboats were successfully launched. The ship sank in just 14 minutes.
In all, 106 passengers and crew lost their lives, including the captain and all the deck officers. Forty-eight are buried in a mass grave by the church in nearby St Keverne.
FACTFILE
DIVING & AIR: Porthkerris Divers, www.porthkerris.co.uk, 01326 280620
ACCOMMODATION:Camping at Porthkerris or B&B or static caravans nearby on the Lizard. Falmouth Tourist Information Centre, 01326 312300, www.go-cornwall.com, www.carrick.gov.uk.
LAUNCHING: Tractor-assisted at Porthkerris
TOURIST INFORMATION: Admiralty Chart 154, Approaches to Falmouth. Ordnance Survey Map 204, Truro, Falmouth and Surrounding Area. Wreck Tour Volume 1, Tour 8, The Mohegan. Diver Guide: Dive South Cornwall by Richard Larn.