Loch Awe survey
How we did it


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We had six weeks, two boats with outboard engines, and a group of personnel that varied from, normally, 12, to 15. Several were Navy-trained divers, the rest were competent amateur divers from the sub-aqua clubs. Four were used to archaeological-level surveying of sites.


The task

Swim every square yard of a 25-mile-long loch and find all the crannogs in it? Ideal target, maybe, but with the team we had, not practical in the time. So the strategy we settled on was to start from what we knew, and work out from there. Our first contact with the NACSAC divers was to tell them what they'd committed themselves to and take them to a crannog to see what they would be dealing with. This was greeted with silence.

Setup

With 60 sites to visit, dive on, search around, and as we had two boats, we split the team in two. Each boat had to have an archaeologist, a competent surveyor, and as many personnel as possible. This boiled down usually to a maximum of five in a boat, rarely six, as maintenance tasks onshore, visits to 'Pussas' to re-victual, people off-colour, people coming and going, etc, kept one or two back from the full team. Due to their military training, NACSAC would organise at least one 'pro' diver in each of the boats, to make sure safety procedures were followed.

Our base, thanks to the Forestry Commission's generosity in lending us two houses, was half-way up the loch, right by a crannog: #4, at Inverliever (click on Crannog 4 on the map, enlarge the top picture, to see some of the houses behind the crannog) . Unfurnished but dry and comfortable, there was room to review and boat-2.jpg - 12184 Bytesdraw up the day's work; and it made for easy storage of kit like compressors. From there we sent the teams by boat for the nearer, by road for the farther-away, sites.

Procedure

On arrival at a site the team would do:
1. a basic evaluation and swim right round the site, discuss and decide whether it was man-made or natural
2. if positive or uncertain, a close examination on the site itself, particularly by the archaeologist(s)
3. tape survey; and extra swim-search around by anyone not busy doing the survey

The first day we simply tried out to see how many sites it was feasible to visit at one stint, and how much surrounding area we could search. This gave us some idea of the scope of what we could do in the time

Luck with the weather

The late summer of 1972 was unusually dry, and quite warm. The loch level was abnormally low when we arrived in September at 117.1'/35.692m OD, almost 4ft (ca 1.2m) below the average level of 121'/36.881m OD. It continued to drop by 1' (400mm) during the exped, to 115.6' OD (35.235m), the lowest in living memory. This meant that some crannogs were sitting completely out of the water, on their natural base; other features like what we called jetties and harbours, as they looked like these (without necessarily wanting to claim these functions) were often just underwater. But other crannogs still had very large amounts of their substructures underwater, with more than normal of their tops exposed.

Whatever, the effect of the low water level was massively to aid our survey. Instead of just seeing a cap of vegetation on a small island, or no island at all, and having to make decisions based on diving, features could be seen in the dry and discussed without the whole team being in the water.

Time

To have all those Naval Air Command divers at beck and call for six weeks would be most archaeological directors' dream. But it didn't work out quite like that. These guys had an annual expedition on their own time: it was meant to be stimulating and recreational as well as research. None of which really applies to heaps of stones in a gloomy loch, virtually devoid of immediate interest in marine-diving terms.

Besides, there was a secondary project for NACSAC on the expediton: Doug Miles' conchological survey, intended for the sea-loch, Loch Sween, and surrounds. This was a good opportunity for a break from the relatively dull freshwater amphibious work, to proper marine diving in clear blue water on the west coast of Scotland.

So in real total, we spent perhaps two of the six weeks in Loch Awe actually on the crannogs. On some marine diving days not all the team would go to the coast; it was a good opportunity for the archaeologists to catch up on drawing plans, keeping records, and a check on results. Other days we went too, and to be frank, it did make a welcome break. Ian Morrison had particularly wanted to dive off Castle Sween to check for any Viking or Dark Age remains offshore, so that took a good couple of days of exploration.

The surveys

During the working time on the loch, activity was needs intensive. Over time, individuals showed talents for particular things, like surveying, or spotting finds/timber, which helped spread the load. At the start of the day, each team would head for the nearest listed site. Not all the sites on the checklist were equal. Local knowledge from residents or antiquaries helped rate some sites as very likely (eg Campbell and Sandeman's inventory of monuments in Mid-Argyll named two crannnogs in the loch); some looked possible from the air; but all had to be checked. Thankfully with the low water level, 'man-made' was very evident when you could see the different profile of built-up crannog stones sitting on a natural mound. There are numbers of natural islands in the loch formed through glacial deposition, of gravel, boulders, clay and sand. Once used to the normal landforms and gradients of these, we could spot artificial building through the sudden transition to regular-sized stones, a steeper profile, curved definite edge to the construction. On a sandy or muddy bottom, the crannog edges were even more noticeable.

But there are always exceptions. Crannog 11 had a built-up projection which we called a jetty, but it took a good deal of examination among the grass before we found that part of a natural island had been floored with regular-sized stones, presumably a house foundation. The rest of the island was not altered that we could see. Perhaps the same function as any other crannog site on the loch, but with much less building effort.

Likewise Crannog 13 normally entirely underwater. Only standing on this very low, shallowly built-up natural island could we see the timbers and stone settings in the floor no very obviously different edge profile from the natural.


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The Murray & Pullar Scottish Loch Survey (1910, six volumes, folding maps, hence the centre line) charted over 500 lochs, and sometimes noted even underwater islands. The crannog here (red arrow), above water, to E of Innis Chonell, is #16, Ardchonnell (modern spelling)

Figures

Our aim, after checking the listed sites for that day, was to get two crannogs surveyed per day, for each team if possible, and in the event, not always. As anyone with practical site experience will know, examination and survey run away with the time. (Two a day left the teams pretty tired on return, with kit maintenance and other jobs for the next day in prospect.)

In the surveys we took the highest point of the crannog, marked it, then took compass bearings to, usually, eight markers on the waterline: the major compass points (if line-of-sight available). Using an alidade we took levels on a ranging pole outwards along a tape leading from the centre to the waterline markers. This gave (usually, if conditions allowed) eight profiles on top of the crannog. From there the tape, held by a diver, was led out on the water surface past the edge of the crannog then several metres further, now above the natural bottom. The diver had a ranging pole in his other hand. Resting the pole's base on the bottom you could read its depth to the waterline and the pole's distance from the crannog centre along the tape. Moving in at metre intervals the depth/distance were called out, noting such things as the sort of bottom, the edge of the crannog stones, any break of slope, bedrock, anything notable. In this way eight underwater profiles to the waterline of the crannog were achieved, extensions of the above-water profiles.

Because we knew the loch level every day we phoned the Hydro-Electric Board, who controlled the pumping station, every morning this gave us a constant datum point which allowed all the crannogs to be drawn to a common level. Finds, and timber, were trilaterated using two tapes from the fixed points.

Conclusion

And that's it. The results are as shown in the individual crannog plans, numbered on the left (our original numbering, not Ian's or the RCAMS's: for table of their numbers, click here). The comments are as summed up in the evening after survey or as directly written down while sitting on or by the crannog. All the results were drawn up in the evening of the day they were surveyed, or at latest the next day. With relatively inexperienced surveyors, it was worth going through the actual measurements when they were fresh in the mind, then any real omissions could be corrected by another visit. Figures were drawn up into 1:100 scale plans. Later, when we were back home, smaller (1:500) plans were drawn again from the original figures (see the 'plans/charts' section for these)

This was, from start to finish, a field survey. If we had come to Loch Awe and found no crannogs at all, it would have served a purpose. In the event, we found 20 examples of man-made structures, some so different from others that only full excavation will sort out the reasons for the different shapes and sizes.

Is that it?

Have we found all the crannogs that were built in Loch Awe? Hard to say, probably not. Common sense would say that many structures must have been destroyed since building, leaving no trace. Others may have been built in deeper water, unlikely though this might seem, or some, built on the edge of a slope, could have slid deeper through slippage (like the siting of #15). Due to the dry summer of 1972, it's surely likely that we found most of those within the 10 m depth range, within the parameters of what we were looking for.


One thing we (K and Duncan) have resisted, is the urge to classify on the strength of incomplete evidence (learnt at Stuart Piggott's knee). That has already bedevilled nascent crannog studies, but as it's part of the career process, no doubt it will continue. A field study like this is meant to be a first look, a broad sweep of what could be a group of structures: no finely-finished plans here, and no typologies!




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