GREAT
SCREAMING
DRIFTS!

Feel the need for speed? Believe it or not, there are divers who don't call anything under 3 knots a drift dive. Now we know why John Liddiard has go-faster stripes on his drysuit.

Experienced divers are always looking for new challenges to develop their diving skills. It might be deep wrecks, it might be caves - it might be drift-diving.
I'm not talking about the "drift dive in a current no greater than 1 knot" mentioned in training manuals, but those of well above 3 knots. Drift dives on which you have no hope of swimming against the current. Drift dives on which the current flings you along and the seabed passes in a blur of marine life.
Drift dives on which you can spread your arms and play at being ground-attack aeroplanes strafing the lobsters and crabs. Drift dives of the soiled laundry variety.

One diver controls the SMB, the other stays free The second diver uses the SMB line to stay in contact Diver Two manages the buddy line to prevent snags

A few points of seamanship and diving that are universal where strong currents are found need mentioning.
Sudden changes in depth can lead to vertical turbulence in the water, particularly where the seabed suddenly drops over a wall. Think of images of a car in a windtunnel, with smoke-streams marking the flow.
Rising over the bonnet and windscreen, the airflow is smooth. As it gets to the rear of the roof, turbulent eddies start to spiral away as the main flow descends the slope of the window.
With an estate car, the slope is so steep that the entire airflow forms massive spirals as it breaks away from the top of the rear hatch.
Much the same happens as a strong current crosses a wall into deeper water. It tumbles and spirals away from the wall, with smooth patches on the surface marking an upcurrent and rough patches and whirlpools marking downcurrents.
Even the most experienced divers will not be able to control their buoyancy in these conditions. So a high-speed drift needs to be planned to avoid such overfalls, either by diving on the tide that takes you away from these descending walls, or by calculating a strict time limit which will bring you to the surface before you drift through them.
Local skippers will have seen the stretch of water you are drifting at all states of tide and weather. If you are planning a high-speed drift from a club boat, it is commonsense for the cox and divers to drive over the area on a similar tide the day before to gain some familiarity.
Having made such a reconnaissance, on the day of the dive cover the full route again to make sure any changes of condition do not present a new hazard. Until you have built up experience of an area, begin with slower drifts and only a few divers in the water at any one time.
A contingency for which you should plan is an uncontrolled ascent. Don't start a fast drift dive with a heavy nitrogen loading. A serious decompression dive followed by a high-speed drift is asking for a trip to the chamber.
Currents can divide, causing groups to split onto widely diverging courses. While a cox is recovering one pair of divers it would be easy to lose track of others, so an additional "spotter" crewing the boat is a wise precaution.
Every diver should carry a delayed SMB with which to surface, even when one of a pair is using an SMB throughout the dive. Divers can become separated, SMB lines can break. Those watching from the boat need to be aware of this because. once loose, an SMB will drift with the wind while the divers drift with the current.
Where there are no obstacles, a buddy line can be a useful safety aid, but beware of the line snagging and divers colliding like a pair of conkers on strings. While one controls the SMB, the buddy has to control the buddy line. Don't let it drag.
You can also maintain positive contact by using the SMB line itself, with one diver managing the reel and the other holding the line a couple of metres away.
Divers should of course carry whatever surface location aids they prefer, from flags, whistles and flares to EPIRBs.
The following locations are some of the more famous - or perhaps notorious - high-speed drifts. Some I have dived myself, while others come recommended by top local skippers.

JACK SOUND, Pembrokeshire
Anyone who has dived the Lucy off the north side of Skomer will have crossed or travelled along Jack Sound, which separates the island from the Pembrokeshire mainland.
The chart shows 7 knot currents, but my experience of chasing SMBs with a GPS-equipped boat shows localised currents well above that. In anything but a flat-calm sea, enormous standing waves form at the south end during an ebb tide.
During a flood tide, turbulent overfalls with strong up-and-down currents form at the north end. So consider a drift in Jack Sound only on an ebb tide with a flat-calm sea.
For the full drift, the starting point is on the west side of Tusker Rock, where a shelving wall descends to a rock and pebble seabed. Within 5 minutes the depth will be 10m or less as you shoot onto the ledges marked by the Cable, a rock towards the south of Jack Sound. Throughout this stretch you need to swim west to avoid being spat out over the Cable.
Past it, the current splits into streams leading west past Skomer, south to Skokholm and south-east towards Dale. A large group of divers could get spread over a dangerously wide area, so one pair in the water per cover boat is prudent.
South of the Cable, the seabed continues as a series of angled ledges, slowly getting down to 24m. This is the prettiest part of the dive, with rocks covered in dead men's fingers and jewel anemones, lots of ballan wrasse and all sorts of clinging crustaceans.
The potential for messing up this dive is so high that you won't find a local skipper prepared to drop you in. However, Steve Lewis of Pembrokeshire Dive Charters is an enthusiast for missing the first bit and starting the dive about 100m south of the Cable in 18m or so of water. For the loss of 1 or 2 knots maximum speed, this avoids the cover boat having to follow an SMB through standing waves and any risk of getting spat out.
It is much easier for the boat to keep track of a larger group of divers, though there is still potential for SMBs to head off in all directions as the current splits. I prefer this version of the dive and, believe me, once you're down there it's plenty fast enough!

Pembrokeshire Dive Charters, 01437 781569

FALLS OF LAURA, Oban
The Falls of Laura mark the entrance to Lough Etive, beneath the Connel Bridge. Water builds up in the narrow channel to the point at which a seawater waterfall develops, and currents reach 14 knots.
One benefit of this dive is that you can take a walk the day before and look down from the bridge to get some idea of what you're letting yourself in for.
There is a step in the seabed from 12 to 30m just after the channel enters Lough Etive, and on an incoming tide this causes violent vertical turbulence. Andy Jamieson of Alchemy Diving recommends drifting the outgoing tide for all but the most experienced divers who have already made the dive a few times.
Entering in the slack water to the south of the lough, divers can swim beneath the strongest current to explore the wall and the remains of an old wooden wreck before ascending the wall cautiously.
Near the top,the ebb tide will suddenly pick you up and propel you along the labyrinth of gullies that cut the seabed. While the floors of these are often scoured clean by the tide, the walls are solid with marine life.
Patches of anemones, hydroids, dead men's fingers and sponges flash past.
Divers often encounter in the gullies tope or spurdog, members of the shark family a lot larger than the average dogfish. SMBs are a nuisance while making this drift. With a constrained and sheltered channel and good boat cover, it is quite safe to wait until you ascend to pop a delayed SMB.

Alchemy Diving, 01631 720337

PIPER GUT, Farne Islands
The dive in the Farnes I had in mind was at Whirl Rocks, more of an industrial-strength washing machine than a drift when the tide is running. However, Ian Douglas of Sovereign Diving told me Piper Gut was just as fast but both safer and more predictable in terms of current direction.
Piper Gut is the channel between Big Har Car and the Warmses. The seabed is a rocky slope covered in dead men's fingers and jewel anemones and sprinkled with wreckage, at least some of which comes from the Forfarshire, the wreck that made Grace Darling famous.
This dive is best made on the flood tide, when the current is flowing southwards. Drop in to about 18m out of the main current, giving you time to get sorted out at the bottom. Many divers prefer to descend without an SMB and send up a closed-end delayed SMB at this point.
It is essential to have a marker on the surface before you get into the main current, because of the many tripper boats that tour the Farnes.
As you swim into the current, you ascend past a lip at 10m and suddenly take off. Once in the current you have to work hard to avoid being pushed downslope and out of the main flow, to stay in the fastest-moving shallow water. Top speed is 4 to 5 knots on a good spring tide.

Sovereign Diving,01665 720059

MENAI STRAITS, Anglesey
The Menai Straits is a long stretch of water and can offer several drift dives that are quite fast enough for most divers. I remember a trip to Anglesey once that was blown out by bad weather, and the only option open was a high-speed drift between the two bridges across the Menai.
We dropped in to visibility of less than 1m at slack water, and the current was soon screaming north with the floodtide. A carpet of anemones swept past in the spotlight beams of our torches, the occasional crabs and lobsters crouched low to avoid being pulled loose. What looked like a big rock loomed before me and I put out a hand to fend it off. My hand sank up to the wrist into an enormous grey sponge.
Scott Waterman, skipper of mv Quest, helped me to fill in the diving details for this one. He suggests starting at Swilly Rock on low-water slack, approximately 11/2 to 2 hours before low-water Liverpool.
The floodtide is recommended, as there is usually less boat traffic. Jump in towards the end of slack, which lasts all of 5 minutes. Descending the rock, you pass the remains of a trawler and a big square block of stone lost with a wooden barge when the Menai Bridge was being built.
The current soon builds to a maximum 6-8 knots on a spring tide. Conventional SMBs are best left on the boat in the constrained waters of the Menai Straits.
To end the dive, divers should swim cross-current to the right (mainland) side and release a delayed SMB.
In late summer, you might even meet some salmon swimming by!

Quest 01248 716923

BURRA SOUND, Orkneys
Most divers who have been to Scapa Flow will have dived blockships in Burra Sound. What they might not have done is drift through the sound, taking a quick look at four ships on one dive!
I heard about this from Ben Wade of Scapa Scuba, when he was standing in as skipper on the Jean Elaine while Andy Cuthbertson was off for a couple of days.
This dive should be made only on the flood tide. Jumping in by the lighthouse about 2 hours before high water gives an incoming current of about 4 knots. Any earlier and it is just too dangerous, with spikes of wreckage on which to impale yourself.
The route goes up and down, deepest point 18m and as shallow as 6m over some sand and gravel banks. As you fly along in typically good visibility, you pass the now-sad remains of the Inverlaine, as well as the Tabarka, the Doyle and the Gobernador Bories.
The dive is usually made without SMBs to avoid entangle-ment with wreckage and to enable divers to fly in behind wrecks, grab hold and take a quick look before shooting off to the next one. I think you need to know the wrecks well to be sure to hit all four in a single drift.
Particular risks here are girders projecting from broken wreckage. Current flows over an intact hull but goes through a broken one. You, on the other hand, might do neither! Past the last wreck, divers can put up a delayed SMB on which to surface.

Scapa Scuba, 01856 851218

GREY DOGS RACE, Scarba
No review of high-speed drift dives could be complete without mentioning Corryvreckan, the channel that separates Jura from Scarba in Strathclyde and contains some of the nastiest currents and whirlpools in the country.
Corryvreckan is too turbulent and deep for a drift dive, although I have been told that there are some fantastic slackwater sites there.
Nevertheless, just to the north of Scarba is Little Corryvreckan and the Grey Dogs Race.
David Ainsley, skipper of mv Porpoise, is an expert on diving these waters. He describes the seabed as a maze of gullies and overhanging ledges, at a general depth of 25m, dipping to 30m in places and with one ledge, the Ski Jump, rising to 6m.
At either end, the seabed drops away to more than 40m and there can be turbulent up-and-down currents. Marine life is a good mix of soft corals and sponges.
A small island in the middle of the channel gives a north and a south route through the dive. A carelessly dropped boatload of divers can easily split and head off in different directions past the island, warns David. A skipper who knows the site can judge the best drop-off points to keep them in a manageable area and avoid the Ski Jump.
A time limit needs to be set so that divers surface before getting into violent up-and-down currents as the seabed drops away. Arrive at slack and wait for the current to build to the speed you fancy. It won't take long, and if it is running at 4.5 to 5 knots on the surface that really means screaming through the gullies under water.
With a calm surface, this is another drift best done without SMBs, using a DSMB to surface and a flag to attract attention.
Never dive here when tide is against wind. The standing waves that form at the end of the dive are able to overturn the biggest dive boat, and impossible to follow divers through.

Porpoise, 01852 300203

STRANGFORD NARROWS, Northern Ireland
I asked members of Lisburn and Glenavy SAC about drift-diving the wall in Strangford Narrows. The best dive is to the north side of the channel on the incoming tide, they told me, beginning well after the ferry jetty to avoid the drift conflicting with the ferry route and strong up-and-down currents.
"Strangford" is a contraction of "Strange Fjord", and strange is the word for this drift. Further north of the ferry, the seabed slopes to 25m, then breaks into a wall dropping to 60m parallel to the side of the lough. Surface currents reach up to 7 knots and submerged currents can be stronger.
The current along the wall is reasonably smooth, with no dangerous up-and-down currents. Further up the slope, there are often back-eddies and counter-currents, making it possible to drift at high speed for a few minutes before a more leisurely drift back towards your starting point.
Because of heavy boat traffic, including speed boats and jetskis, SMBs are advisable. The cover boat will frequently have to fend off other boat traffic that ignores marker buoys and A-flags.

The club's DO recommends RIB charter from DV Diving, 028 91 464671, and North Irish Lodge, 028 93 382246.

START POINT, Devon
Alan House, skipper of the Kara-C, helped me out on this one. Though Start Point can be drifted on the flood tide, he advises that the current will tend to push divers off the best route, and that diving on the ebb tide is much more interesting.
Alan recommends dropping in to 20m or so on the Hallsands side of Start Point about 500m offshore, just after slack water. The current will pick up and carry you out and round the point, through the area of the tidal race.
SMBs and calm surface conditions are essential, as the prevailing wind will most likely be against the tide.
The seabed is a mixture of rocky gullies with sand and shale patches. As might be expected in any such high-current area, the rocks are covered in anemones and soft corals. Further out are scallop beds that cannot be dredged because of the risk of fouling gear on the rocks.

Kara-C, 01548 511101

GET THE DRIFT?
Having whetted your appetite for a Screaming Drift Dive, there are many more locations to consider. All my advisers seemed to know of other high-speed drifts.
How about Chicken Rock on the Isle of Man, St Catherine' s Point on the back of the Isle of Wight, Portland Race off Portland Bill, Anvil Point and St Albans Head off Swanage, St Davids Head and Ramsey Sound in Pembrokeshire, the Pentland Firth between Orkney and the mainland and many more locations on the west coast of Scotland?
There are no doubt many other places where you can enjoy the sensation of speed. Just remember to gather as much local knowledge of a site as you can, start slow and build up and, above all, pack a spare pair of Y-fronts.

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Appeared in DIVER - September 2000

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