Another dive on the wall - Britains 20 biggest wall dives

THERE IS SOMETHING MAGICAL about a big wall dive. At the outset, we can free-fall into the blue, green, or even black, with nothing but emptiness below and the wall sliding by our sides. Then, for most of the dive, we hang neutrally buoyant, chilled out while just floating past the anemones, gorgonians, dead mens fingers, crabs, lobsters and crawfish.
When its time to ascend, there is something to look at on the way up, and on the perfect wall dive we can even continue to admire the marine life on a 3m stop.
Its the sort of experience that dive computers were invented for, where you can multi-level to your hearts content, or until you run out of air.
In practice, in average British vis, a wall that drops for 20m or so is all we need to get the full experience. Still, the mystique of knowing how much deeper it goes adds something special, even if youre not going there.
Similarly, even though our dive ends when were back at the surface, looking up to see a cliff looming above us adds that extra wow.
So where are Britains biggest wall dives, from the deepest point below the water to the highest point above Where can the numbers alone add the biggest buzz to the wall experience
I will set my ground rules. There must be at least 20m of real wall below the water, no matter how high the cliffs are above, and no matter how deep the slope ends below. This rules out famous locations such as Beachy Head and Lands End, and many sea cliffs in England.
They were all eroded from hills by wave action so, while looking spectacular above the water, they translate into gentle slopes as soon as we are below the waves.
I dont expect a wall to be perfectly vertical from bottom to top. Some sloping sections, buttresses and ledges are OK, as long as it is overall a wall. A narrow bench just below the waterline is only to be expected, where waves and storms have cut into the cliff, but it can only be a small step in the overall wall, disqualified if it becomes big enough to be a dive by itself.
Where walls get really deep, there are only numbers on the chart to go by, rather than diving experience. To be fair to the walls within sensible diving depths, I have used numbers from charts to list the walls, even where I know that the wall ends and the slope begins before the maximum depth is reached.
For convenience, depths below sea level are given as negative numbers, while heights above sea level are given as positive numbers.

HERE MAX, MY DOUGHTY ASSISTANT, fielded it and released enough air from it to allow me to wind it back down, replicating an ascent without my actually going anywhere.
This allowed me to notice any tendency to over-run and birds nest as the reel span free, and to wind the line back in with a similar tension to that of a diver keeping a line taut during an ascent.
Birds-nesting is a term familiar to anglers.
It occurs when your neatly wound line suddenly gets irrevocably tangled around the reel-spool.
Remember that a line rarely goes up completely vertically. The buoy will be subject to current and wind, so you will need a lot more line than the depth from which you plan to deploy it. Think in terms of 50% extra.
Never attach a reel or spool to yourself or to your equipment when launching a delayed SMB, as you might get dragged up with it.
Many of the reels described here are available in larger sizes for longer lengths of line. These 15 represent only a small selection of what is available on the market. They are arranged in price order - from £18 right up to £105.


TOP: -5m
TO: -42m
DROP: 37m

The Runnel Stone, to the south of the Land's End peninsula, has always been a wreck magnet. Salty sea tales claim that there is no rock at all, just a pile of wrecks. However, like most of our walls in Cornwall, the Runnel Stone formed as a mass of volcanic granite, as did those you can see topside on moorland.
With any surrounding softer rock eroded by the sea, the faces of the remaining reef are often vertical.
The last ship to be wrecked here was the City of Westminster, on 8 October, 1923. The wreck now lies against the west side of the rock (Wreck Tour 4).
The reef used to just break until the City of Westminster knocked the top off, so before 1923 the drop would have been 42m.
From the flat top at -5m, all but the north side of the Runnel Stone drops vertically, with the east side being the immediately deepest wall to about -25m. To the south, a canyon needs to be crossed to a deeper flat rock at -10m, which then drops pretty much vertically to -35m. From here, a sand and boulder slope heads deeper.


TOP: -6m
TO: -45m
DROP: 39m

There are numerous walls to dive on the Manacles reef to the east of the Lizard, but few meet our criteria for a 20m drop, and the biggest of these is on the Raglan.
From a narrow, kelp-covered ridge at -6m, it drops vertically on all sides. The initial drop means that the rock can be easily circumnavigated at -15m, but going deeper the reef structure becomes more complex, and spreads out. To the south-east, a narrow step leads to more wall, a sloped section, and a final section of buttressed wall that drops off the edge of the Manacles to -45m.


TOP: +3m
TO: -39m
DROP: 42m

Just south of St Peter Port, the rocks of Anfre and Piette are part of the same reef system, with a wall dropping away to the east.
Here the rocks form a series of jagged ridges as the reef steps away, with the steepest stretch of uninterrupted wall to the north-east, dropping to -39m.
The Channel Islands have notoriously big tides and screaming currents. The inside of the reef can be drifted, but slack water is required to dive the wall safely. At high water the dive could be 10m deeper and Anfre submerged, but the overall drop would be the same.


TOP: -9m
TO: -54m
DROP: 45m

Back on Cornish granite, Hand Deeps is a close neighbour to the Eddystone. Both are sprawling reefs with ridges and gullies and multiple peaks.
The Eddystone breaks the surface, and is marked by a lighthouse. On Hand Deeps no rocks actually break, the shallowest point being -9m, right at the northern extremity of the reef. From here, the rock slopes to the north at 45° to -15m, then plummets vertically to -40m before a boulder slope continues down to the charted depth of -54m.


TOP: -15m
TO: -60m
DROP: 45m

A little further west from Hand Deeps, Hat Rock is a wide turret of granite that rises from a general seabed depth of -60m to peak in a plateau at -15m to -20m.
On the north side there is a sharp 90° edge, where the flat reef suddenly goes vertical and drops away. While this is the deepest-reaching wall so far, Hat Rock is also the deepest-starting wall in our list, so the overall drop is only 45m.


TOP: +3m
TO: -45m
DROP: 48m

Payne's Rock is located off the north-west side of Skomer Island, about 200m offshore and 500m south of the Garland Stone. The rock can be circumnavigated at -10m, but the deep wall is only on the outside face.
The photographic irony of diving a wall is that while the overall scene is big, the best photography is often macro. This is particularly true on Payne's Rock, which is great for nudibranch-spotting but rarely good for big scenic pictures. For some reason it is always a bit of a dark and foreboding dive.


TOP: +29m
TO: -42m
DROP: 71m

One of the most impressive scenic dives in the Skomer Marine Nature Reserve is the Garland Stone reef, stretching north from the Skomer side of the Garland Stone. However, the biggest wall is on the west of the Garland Stone, where the face drops almost straight to -42m. It is usually much lighter than Payne's Rock, but bare compared to both Payne's and the nearby reef.


TOP: 0m
TO: -75m
DROP: 75m

I confess that there are numerous rocks in the Scilly Isles that meet my criteria for a wall dive with an underwater drop of at least 20m. If I had listed them all it could have wiped several walls so far off the bottom of the list.
Deep Ledges is almost the northernmost reef in the Scillies. Running from the surface to the deepest water it has the biggest drop, but I suspect that it breaks into a slope before it gets to -75m.
The deepest I have dived here is to 40m, and it was vertical as far as I could see below me.
Nearby on the chart is John Thomas Ledge, but it drops only from -7m to -25m, for a total of 18m, so doesn't even meet my basic criteria. I haven't dived it, but it would be a fun name to have in a logbook.


TOP: +10m
TO: -70m
DROP: 80m

While big walls are scarce in the southern British Isles, once we get far enough north for glacial geology to reign just about any loch or channel has numerous walls that disappear beyond normal diving depths. If I played fairly, the South would hardly feature on the list.
To the north of the Sound of Mull, Calve Island guards the entrance to Tobermory Harbour. A short cliff above a narrow shoreline rises only +5m, and just behind it the highest point on the island is only +10m. Below, a bouldery slope drops quickly to -3m, then simply goes vertical, even overhanging in places.
After the dive, the wonderful pubs of Tobermory are conveniently close for some additional decompression.


TOP: +37m
TO: -60m
DROP: 97m

One of the more remote walls on our list, Sule Stack is usually dived for the wreck of the Greek motor vessel Manina, which struck on 8 April, 1968, and now lies scattered down the wall and the slope below.
The south side of the stack rises +37m above the sea, and is pretty much vertical as far as -35m below, before breaking into a boulder and sand slope that continues down to the charted depth of -60m.
In addition to wreckage, divers occasionally find ammunition. The rock was once used as a gunnery and bombing target, a hobby the Navy and Air Force can no longer pursue out of consideration for all the birds that nest there.


TOP: +60m
TO: -40m
DROP: 100m

The third and final of our trio of Skomer Island walls, which I justify including because they are such remarkably different dives for such a small area.
The North Cliff runs all along the north side of Skomer Island, from the inlet of North Haven to the Garland Stone. The steepest and deepest section is from the point by North Haven along to the next buttress.
Take care not to break any of the gorgonians that grow along here. Many are part of a long-term growth study by the Marine Reserve staff.


TOP: +44m
TO: -60m
DROP: 104m

Named Wolf Rock because of the way the wind howls over the reef, this is our highest-ranking reef of Cornish granite, and that is only because I cheated. The reef rises only to +3m, but the lighthouse adds another 41m.
I figured that this was only fair, because the Runnel Stone lost out when its top was knocked off.
The lighthouse is made of dovetailed blocks of granite in a design that draws on that of the Eddystone. It took nine years to build, and entered service in 1870.
Before it was built, an iron day-mark post erected in 1795 lasted less than a year. That was followed by an iron and concrete conical beacon built between 1836 and 1840. It can still be seen standing by the lighthouse.


TOP: +65m
TO: -46m
DROP: 111m

Off the tip of Little Sark, L'Etac marks the southern extent of the smallest self-governing island in Europe.
The wall here drops to -40m before continuing in a slope. As is the case in Guernsey, a high-water spring tide can make this 10m deeper. To the east, Les Vingt Clos has a similar wall, but the reef only just breaks.


TOP: +70m
TO: -46m
DROP: 116m

I was in two minds about how to include Strumble Head in our list. While there are big cliffs above the sea, the wall below is broken by a fair shelf at 10m, and the cliffs go up in terraces.
In the end, I credited Strumble Head with the maximum 116m drop, purely because it was too difficult to draw the line anywhere else.
Towards the Penbrush end of the wall, the remains of the steel-hulled barque Calburga are in 43m. A gale on 13 November, 1915, stripped the sails, broke one of the three masts and blew the ship towards the cliff.
The captain wisely abandoned ship before it was dashed against the rocks, guiding the lifeboat with all 14 crew safely in to Aberbach.


TOP: +3m
TO: -120m
DROP: 123m

If I can include the height of a lighthouse, I can include that of a pier. The wall beneath the old pier at Lochaline can be accessed as a shore dive, but is much easier from a boat, especially with the ferry slip round the corner being so easy to launch from.
Beneath the legs of the pier is the usual horde of debris, which continues as you descend the wall, caught on many of the small ledges.
The easy access to depth makes it a convenient technical training site for the nearby dive centre. The wall is reported to break into a slope from -90m onwards.


TOP: +125m
TO: -77m
DROP: 202m

Dunnet Head is the real northernmost point of the mainland British Isles, looking out over the Pentland Firth to the Orkney Islands, and is one of many great Caithness dive sites most divers bypass on the way to Scapa Flow.
Round most of the headland, a wide shelf to -15m almost disqualifies this wall, but the shelf narrows enough in a few places that I decided to include it. At -15m there is a rounded 90° lip, and the wall plummets.


TOP: +175m
TO: -71m
DROP: 246m

The size of the volcanic scenery at St Kilda is deceptive. It is only when the boat is right below it that the scale of Stac Lee becomes apparent. On the east side it goes straight up to +175m and straight down to -45m, punctuated by a large cave about halfway. From -45m, it breaks into a rocky slope that continues to the general seabed depth of -71m.
With typical St Kilda visibility, this is one of the few walls where you can really appreciate a drop of more than 20m.


TOP: +110m
TO: -188m
DROP: 298m

The North Wall of Rathlin Island, off Northern Ireland, drops into the scour of the North Channel, and some of the deepest coastal water in the British Isles.
The maximum drop can be found just back from the lighthouse, where a narrow sloping shelf at the shoreline soon drops away, with a pair of arches on a short terrace at 40m. Below this, where the wall ends and the slope begins is anyone's guess.


TOP: +5m
TO: -315m
DROP: 320m

Here we have real depth, and very little above. The Inner Sound of Raasay is a submarine test range, and while tests are taking place loud sonar pinging can be heard above water. I hate to think what it would sound like below, so contact range control on the VHF radio before diving, to make sure you don’t end up turned to jelly.
From the towering +5m height of the day-mark beacon on top of Rubha ard Ghlaisen, the wall descends in smooth glacial bumps to the deepest coastal water of the British Isles at -315m. If Raasay Island wasn’t so flat, the drop could have made first place.
Perhaps someone should build a 30m lighthouse to replace the beacon at Rubha ard Ghlaisen.


TOP: +290m
TO: -45m
DROP: 335m

Hirta, the main island of St Kilda, is built on an even bigger scale than Stac Lee. The highest cliff is at Conachair, +426m above the sea, but the shoreline below extends in a boulder slope, thus disqualifying it from our list of big wall dives.
Our definite number 1, without any cheating by me, is Oiseval, where the cliff rises +290m straight up from the sea and descends -45m below. Once at St Kilda, it makes a strenuous but short afternoon hike to the top, just for the sake of looking over and appreciating the scale of this cliff.
To get a perspective, the tallest building in London is Canada Square at 235m, and the London Bridge Shard, now under construction, will reach only +310m.
Somewhat ironic, with this as the biggest wall in Britain, is that most divers who make it to St Kilda are hardly concerned with wall diving, as they head into the numerous caves and tunnels below.