Three hundred miles off the Scottish mainland and eighteen hundred miles east of Newfoundland, a light flashes every twenty seconds on a low pinnacle of rock breaking the emptiness of the North Atlantic. This is the island of Rockall, Scotland’s remotest territory and for transatlantic passengers from Prestwick, a tiny black triangle forming the final outpost of Europe. Swirling water nearby marks the sites of two other pinnacles just below the surface, Hasselwood Rock and Helen’s Reef.
The three rocks are the only visible signs of a submerged micro-continent the size of Ireland, foundered into the deep Atlantic as Europe and North America were drawn apart over a period of more than a hundred million years by convection currents within the mass of the earth. When energy shortage makes it economically worth tackling such a difficult area, this micro-continent and its surrounding waters may well become the source of oil.
On a normal day the rise and fall of the long Atlantic swell, breaking into whiteness, climbs half way up the seventy foot sides of Rockall Island, and in storm conditions water sweeps clear across its summit. The powerful turmoil over the two concealed rocks couples with the menace of the island to give the vicinity a gruesome aspect which has for long ensured that mariners leave it a wide berth.
Research into the structure of the sea bed in this area has been carried out for some years by the Institute of Oceanographic Sciences and Cambridge University; more recently small drills of the Institute of Geological Sciences have been manoeuvred onto the rock outcrops with the help of closed circuit television. Diver scientists worked on Helen’s Reef in 1972.
By 1973 critical areas which could most usefully be looked at in detail by putting scientists on the sea bed in a submersible had been identified.
A technique of close examination of key underwater outcrops, from which conclusions can be widely extrapolated, was developed mainly in the course of three earlier series of dives in the Sea of the Hebrides and the Minches in 1969 to 1971, using the Vickers submersible Pisces II.
During the eight days in June 1973 a total of fourteen dives was undertaken on Rockall Bank with the sister submersible Pisces III. The study was carried out by marine scientists of IGS and IOS, and commissioned by their parent body, the Natural Environment Research Council. The nineteen foot long submersible operated from her mother ship, m.v. Vickers Voyager. Prior to the widely publicised accident on Pisces III off southern Ireland in August these submersibles had established a good safety record in the course of four years of intensive work in British waters, and in view of stringent precautions their operation had become regarded as involving no worse risk than most human activities. despite an uncomfortable 6 to 10 ten foot swell, on none of the Rockall Bank dives were there any incidents involving potential danger to the submersible or her crew.
The launch procedure starts with a series of checks by the duty pilot whilst Voyager comes slowly round onto launch course, selected as most suitable for the weather. Pilot and scientist observer then enter through the conning tower via a gangway for the deck level above the submersible well. the submersible is winched backwards on a rolling platform until it lies on the stern below a large moveable ‘A’ frame, and the hatch is closed during a distance countdown received by radio from the bridge.
The pilot lies on the port couch inside the 6ft 6in diameter personnel sphere, and the observer opposite him on the starboard couch.
The sphere is in the bow of Pisces, which is mounted facing astern on the mother ship, so at this stage all three observation portholes look backwards onto the wake of Voyager. The observer has ready-to-hand press buttons for two external characters, one fixed and one mounted on a pan-and-tilt mechanism alongside a TV camera linked to a screen and videotape recorder in the cabin.
Another press button is available to record events on an IOS ‘black box’ which continuously monitors vehicle direction, depth and current direction. In addition the observer carries two parallel audiotape recorders and a quality camera for use through the portholes. External tools include a small rock drill, sediment scoops, a manipulator arm and a sample basket.
For the crew a launch starts when the hatch is closed. There is a hush as outside noises cease. This is a time for swapping Christian names, if they are not already known and for running over emergency procedures. ‘Steady course, steady speed’ is announced by the bridge, the distance countdown continues; as the launch site is approached there is a slight jolt and the submersible is swinging in the ‘A’ frame. The gentle swaying continues briefly, then follows a ragged splash and surge of water past the portholes; a feeling of steady powerful pulling as the vehicle is towed backwards at about two knots. there alternating glimpses of sky, waves, bubbling water and cascading rushes of sea held into globules by surface tension on the thick plastic of the portholes.
Sometimes sky and waves are grey and the bubbling water green; sometimes sky, waves and water are sparkling blue, with shafts of sunlight; sometimes the sea is calm, disturbed only by the slight wake of the mother ship; and sometimes there are what seem to be great white capped rollers advancing past the tiny craft. The crew wedge themselves in and wait; it is curiously comforting to feel that at this stage one has no responsibility for decision or action.
Once the main hoist and the tow lines are detached by a diver the submersible takes on the full motion of the waves. Sonar (high frequency sound) voice communication is established and the order to vent the buoyancy tanks is given from the mother ship; there is a slight backwards inclination as the stern submerges first; the vehicle appears to hang to the surface, as if reluctant to depart. There is a profound silence, broken only by the pilot’s periodical reports to the dive controller on the mother ship, his curt acknowledgements and the click, click, click of the echo sounder heard on the sonar communications system.
As the light fades into the greyness the submersible has entered into another world as olds as life itself. A myriad tiny animalcules drift slowly upwards past the portholes, suspended in limitless space like stars. Occasionally there are hosts of jellyfish, gracefully trailing long streamers, but mostly the impression is of a great variety of minute forms disposed in seeming peace and silence, each gently adjusting its position slightly in relation to its neighbours. The sinking bulk of the submersible throws this quiet world into tumbling disorder, bedraggled tentacles are draped flapping over projecting instruments and the little organisms nearby are caught briefly but helplessly in swirling vortices, whilst those beyond the reach of the movement retain their grace.
As light fades the pilot switches on some of the external lights, and the animalcules are illuminated against a backcloth of darkness. An internal echo sounder indicates the approaching sea bed from 100 feet away, a flickering green light drifting slowly round a circular scale graduated from 100 to zero. At about 40 feet above bottom the pilot starts to motor slowly ahead so that he can be sure to land in an area that he has been able to inspect. The site has been selected in a flat patch, but the amount of sideways drift in the course of the descent is not known precisely and there is need to guard against the unseen stern of the submersible landing awkwardly on some unseen projection.
As the sea bed appears mistily below the limit of visibility the descent is slowed to a gentle hover, causing only the slightest of jars as the skids touch bottom. The few minutes after landing are reserved for setting up the scientific ‘black box’ and for obtaining from the mother ship a precise position of touch down to plot on a large scale plan, to enable the crew to see exactly where the craft lies in relation to topography earlier recorded. A heading is selected, the pilot checks with a scanning sonar that the route is clear and relays the intention to the mother ship, recorders are switched on and a stream of scientific observations and photographs begins.
In 1973 there were three main zones of study on Rockall Bank: concentric rings of igneous rock ridges in the north near Rockall Island, outcrops of ancient rock like those of north-west Scotland in the centre and south, and thickets of cold water corals flourish at depth on the flanks.
Most of the dives involved traverses averaging perhaps a mile in length; working depths varied from 335 to 1400 feet. A total of 924 photographs were taken and 56 samples collected.
The general picture is that from a great plateau of white sand rise several extensive patches of rocky outcrop forming ridges and pinnacles. There are areas of cobbles, some associated with a time associated with man’s pre-history when the sea level was some 600 feet below the present and enough of Rockall bank was exposed to form an Atlantic island nearly as large as the mainland of Scotland north of the Great Glen. The spreads of sand are almost entirely the remains of countless marine animals, a graveyard of a size beyond comprehension. The coarser material in shallower water is disposed in sharp crested symmetrical sand waves many feet across, stretching in straight lines into the darkness, deposited by the latest storm. In deeper water, where wave disturbance is reduced, finer material is pitted and churned by feeding trails and by the prod marks of feeding fish.
The sand ends abruptly against the rocky outcrops. In shallow water where there is enough ambient light it is possible to switch off the floodlights at the edge of a sand plain and descry rock buttresses and foothills leading to distant craggy summits with vertical cliffs, like some lunar landscape. Pisces normally travels on its skids across sand, but can fly at a height of a few feet above irregular remains; hover and nudge its way up cliffs, and if desired set down halfway up a peak to collect a sample. The procedure is slow but in the hands of a skilled pilot not without a certain grace, rather like that of a weightless elephant feeling its way across the landscape.
The lights of Pisces seem to frighten away many fish. Pale wraiths sometimes gather when the lights are off only to disappear in a flash of fins when they are switched on. Dogfish adopt an attitude of indifference, almost of contempt. A number of bottom dwellers hold their place in the face of the advancing submersible, relying on their camouflage. One can only hope, with some misgivings, that they realise the need to temper bluff with discretion before the skids reach them.
Occasionally the submersible finds itself in a close packed shoal of darting fish peering in the portholes; elsewhere small agitated brown crustaceans cluster round the lights like dense swarms of miniature bees.
When the dive objectives are achieved permission to ascend is requested from the mother ship. There is a pause while Voyager moves away to leave the ascent position clear. This is a time for getting equipment in order, for biscuits and a cup of coffee from a thermos flask, time also for a chat. The external lights are off and there is total peace. the deep sea is a peaceful place. It is not hostile; it simply has its own rules.
The ascent is like the descent in reverse. As ‘50 feet to go’ is signalled to the mother ship daylight is replacing half light and the submersible is beginning to take on a slight swaying motion in addition to its upward urge; this increases rapidly, culminating when the upper part of the vehicle leaps clear of the waves in a boiling rush of water and bubbles. As the submersible wallows, waiting, the crew experience the most uncomfortable part of the mission if the weather is poor, swaying in all directions at once and wedging themselves in the best way that they can.
The mother ship has positioned herself down weather where she can move forward against the swell for the recovery, advancing so as to pass close to the submersible. An inflatable work-boat has deposited a diver on the conning tower and returned astern of Voyager to collect the tow rope, veering out from behind at the critical moment and handing the rope to the diver. The line is connected to the stern of Pisces and within seconds she is on tow backward at about two knots, prior to being hauled up near Voyager’s stern for the attachment of the heavy hoist rope.
A clunking noise indicates the hoist attachment complete and almost at once the motion changes again to a different sort of swaying, with water cascading past the portholes and glimpses of sea, breakers and the attendant inflatable astern of Voyager.
The ‘A’ frame swings over and the skids scrape down on the rolling platform, which is quickly winched back inside the vessel as the pilot blows a little oxygen to push the hatch open; there is a light spatter of drips, then the ladder is in place. The time has come for the meal that has been kept hot in the oven and for the start of the debriefing session.