IntroductionDiver Training & Qualifications
As can be summized from the title, diving was very much an integral part of the expedition. Our objectives were to carry out the first geological survey of this unique underwater environment, to make a photographic record and to bring back samples, all of which we achieved, all these objectives required some diving input.
The diving was purely exploratory, we had only a vague idea of what to expect, based on the few land-based photos by the man (Hans Pauly) who first reported the occurrence in 1963. There were no underwater photos.
Divers view
From the (land based) photographs we had seen, we much expected
the ikaite to form only small reefs or skerries. However, not only did
it form these skerries, but also spectacular columns. These columns which
were as varied as they were many, were not evenly distributed and gave
the diver the feeling of moving through a petrified forest, often the columns
would be packed together like some dense thicket, but occasionally they
stood alone like an oak in a forest clearing.
The fjord itself is about 10 km long, is hemmed in on both sides by mountains rising up to 700m and approaches 200m at its deepest point. However the 3km region near the head of the fjord in which the ikaite is located, is relatively shallow, with a 'charted' depth of about 28m. During the period in which we were there, the fjord experienced a maximum tidal range of about 4m on spring high water tides. As a guide to tide times we were able to use the tide tables for Arsuk Fjord (to the North), though tidal prediction was not a crucial matter as far as diving was concerned.
So what were the water conditions like? Interesting is the best description. The Fjord though generally ice free in the summer months - one ice berg did come to visit us - is very close to the interior ice sheet and consequently gets a continuous supply of water. Fresh water also seeps in from underwater springs. This results in a surface layer of fresh water up to 4m deep, overlying the sea water. The boundary between these bodies of water (a halocline), appears as a shimmering layer, and also represents a distinct thermocline. With temperatures above it of about 13oC and below it, averaging about 3oC, but on occasions, such as after heavy periods of rain, reaching almost zero. This interface which could be said to offer a perfect combination for the lazy diver, allowing him to effectively 'wash' down his kit at the end of every dive - an important task, required some careful buoyancy control - a diver would find himself suddenly negatively buoyant on approaching the surface at the end of a dive.
Whilst reports of 'gin clear' visibility were generally true for the fresh water, the reports might be considered somewhat of an exaggeration for the sea water. Visibility was generally excellent in the first 5 or 6 metres, in fact unnervingly so when coxing the inflatable, as you continuously thought you were going to rip the bottom off the boat, when travelling over the large columns poking up from the depths. We later discovered that these pinnacles were always at least 3 metres beneath the surface. Beneath this, the visibility was generally moderate to good, at up to 8m,
Other than directly at the bases of the large ikaite columns, most of the bottom was covered in a soft fine mud, albeit quite thin in places, which stirred up if you even showed it your fins. On the number of occasions that had us working on the fjord bottom, visibility was often reduced to zero, luckily however, there always appeared to be a slight current, which quickly carried away anything kicked up. We also had a slight problem with plankton towards the end of our stay - not just a problem in the UK!
Of the six expedition members, two joined the team as non-divers. Though the expedition could have functioned with only four divers, it was considered expedient, for efficiency, possible health problems etc to train them to dive as well.
With our equipment leaving by sea freight in May, it was first decided to attempt to carry out their Novice Training over a long weekend, in the usually relatively sheltered waters of Swanage Bay, however the weather and conditions conspired against us, so that our trainees could only get to experience snorkelling in zero viz.
Practical training was then switched to weekday evenings in whichever of our club nights was available. This slowed matters down considerably and inevitably the day came when our kit was shipped, without our trainees having completed their open water assessments. Not put off, we still managed to get the open water assessments done, but only with whatever bits of kit we could cobble together. This shortage in equipment meant that when we arrived in Greenland, neither of our trainees had yet used drysuits, nor either a pony or twin tank set-up, and excluding the 'Swanage experience' had only completed up to four dives a piece.
The qualifications of the remaining expedition members, were Sports Diver, Dive Leader & two Advanced Divers, of which one was an Advanced Instructor. All had been diving for some time and were suitably experienced. In terms of BSAC branch positions this experience could be seen, in the fact that at the time of the expedition, the team comprised two Diving Officers (TGSAC + LGUSAC) and one President (LGUSAC).
Though on paper the idea of taking two novices on an expedition dive in possibly extreme conditions, might not look too sound, in reality as for general safety reasons, all dives were expected to be no-stop and as the novice divers did not have to be relied upon if conditions were too severe and further as the other members were eminently experienced to look after them, it was not considered a problem.
In actuality, conditions were nowhere near as extreme as they could have been. Most diving was very shallow and the fjord generally offered sheltered conditions akin to UK inland sites. The novices were of course of great use and had few problems.
Though the majority of the expedition members had had experience through their degrees in surveying, it was considered prudent to learn as much as possible about underwater surveying techniques and how to apply land techniques to underwater problems. To assist in this aim therefore, most of the members undertook the 'Archaeology Underwater - Part 1' course run by the Nautical Archaeological Society (NAS) in early march. The two day course combined 8 hours of theory with a mock underwater (swimming pool) survey.
As in all diving, safety was paramount in our plans. The nearest recompression facilities were in Canada, and though we were able to borrow an oxygen kit from the Royal Danish Navy - oxygen is the only effective first aid for any decompression illness - we decided to take no chances. For this reason, all dives were planned as No-Stop dives, using BS-AC '88 Tables. As a back up some divers also carried dive computers. On the one occasion that divers exceeded a no-stop dive according to the tables - on one of the deeper circular searches - the dive registered as a no-stop dive on a computer carried by one of the divers. Never the less the 'deco' stop was undertaken. Divers were also advised to do no more than four days of continuous diving, again as a precaution against decompression illness.
To offset the need for rapid ascents in the event of a free flow, a real possibility in such cold water, all divers carried either a twin set or pony, with independent regulators. As a precaution against such free flows happening at all, where possible, the regulators were environmentally sealed. This being said, free flows are more likely in high performance regulators and of the three free flows experienced, two occurred with high performance environmentally sealed regs!
We all wore drysuits of course, with wet hoods and gloves. Dry gloves were tried but were found awkward to use and generally abandoned.
The first few days of diving (and the expedition itself) were put aside for orientation dives to the surrounding underwater geology and conditions. All members had to sort out their buoyancy, as they were either using a new dry suit, or equipment set up, or both. On top of this, our novices still had to learn how to use their drysuits. At the end of these few days the team were also well versed in the operation of the compressor and in boat handling.
Diving continued on an exploratory nature, looking for trends and differences in column morphology, this being incorporated with photography and filming. This diving was mostly as shore dives, as the boat was required for surveying the fjord and in the production of our basic bathymetric and ikaite distribution chart. Next followed an intense period of diving in support of our charting activities. The final dives saw the recovery of our samples for transport back to the UK.
In total 95 dives were undertaken on the expedition, amounting to just over 35 hours underwater. This works out at about 3 dives per day, versus the maximum envisaged 4 dives a day. The average depth was about 13m.
To verify the accuracy of our bathymetric / ikaite chart we had to perform a number of 'check' dives. These dive sites were selected on a random basis, with the aid of an 'in house' computer program, and were located by using transits, based on bearings to known markers on the shoreline, also calculated by of an 'in house' program.
For speed, ease and accuracy in setting up, it was decided to employ a circular search methodology for these dives. The basic mechanism of such a search, is that divers swim in circles around a central point. A 'datum line' is run out from the centre of the search area, so that the divers know when they have completed a 360o sweep. The radius for each sweep is kept constant by means of a 'distance' or 'search line'. The sweep radius is increased until the area to be searched has been covered, the amount of increase being governed by the underwater visibility and the size of the object(s) being sought.
The technique and tackle set up was developed by a pair of divers over a number of dives in areas of known ikaite occurrence and then discussed in detail on dry land prior to employment, the technique was further refined in use. The test dives also ascertained the preferable maximum radii (15 metres) of the searches and therefore determined the number of searches that needed to be completed in order to gain a result of statistical significance.
Each location was first marked using a small self-deploying shot. The reason for this being that the shot could be more easily redeployed in the event of it being either wrongly located, or giving a deeper second dive - as a safety precaution against decompression illness, all dives should be undertaken such that repeat dives (whilst the diver has a nitrogen loading), are always shallower than former dives.
The check on depth also allowed for the search tackle to be set-up (as much as possible) for the depth involved, thereby minimizing the scope for tangles on the bottom. This system also allowed a another search area to be located whilst an actual search was being carried out, thereby maximizing time.
On reaching the bottom after the deployment of the search shot, the first task was for one of the divers to run out the datum line, this was always run out further than 15 m so that it would be spotted in the event of the bottom being disturbed by the divers on their search(es). Whilst this line was being laid out, the second diver would sort out the distance line appropriate to the visibility. For the search itself, an outer diver would keep the line taught, whilst the inner diver swam back and forth, recording each of the columns encountered. A note was made not only of the number but also the morphology and size of the columns.
The 15 m long distance line was made up of six 2.5 m sections of floating line. These sections had a loop spliced into each end and were connected together using karibiners. This inbuilt connectivity offered a quick method of increasing the search radii if required and also allowed the divers to easily unsnag themselves when encountering any large columns, thereby avoiding a saw tooth dive profile - which carries an extra risk of decompression illness.
The search axis was set up about a metre above the seabed, to avoid snagging the numerous small columns and weed encountered. This set up also ensured that the bottom was disturbed as little as possible, thereby preserving the visibility.
Having completed our check dives and being confident that our basic chart was indeed quite accurate, we then set about looking to see if the columns were aligned in any particular direction. To do this we used a simple technique that we had learned on the NAS course. The survey involved the laying of a measuring tape as a 'jackstay' between two points.
A pair of divers would swim along this jackstay until a column came
into view, at which point one of the divers would swim out to the column
with a distance line (a second measuring tape). The diver on the jackstay
would then move his end of the distance line back and forth along the jackstay,
until the smallest measurement against the jackstay had been achieved -
in effect, having achieved a right angle.
Both measurements were then recorded. i.e.
[i] The distance along the jackstay and,
[ii] The distance from the jackstay
The normal protocol was for one pair of divers to survey only one side
of the jackstay and a second team the other. Both teams surveying along
the jackstay in the same direction.
One end of the search was buoyed to enable its position to be fixed on our chart.
The initial attempt at setting up our first such survey, was quite amusing, we started by thinking the columns grew mostly out of the mud, so were a little surprised when trying to knock in our first spike, to hit rock. On our next attempt we entered the water like underwater mountaineers, with hammers, spikes, rope, shackles and goody bags etc, prepared for all eventualities.
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