Moving the Bluestones by Sea

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From English Heritage web site

Introduction:  Before I visited Stonehenge I explored the English Heritage Stonehenge website.  The map showing the route by which the “Bluestones” might have been brought by water immediately struck me as ridiculous.  Whatever the craft they used, why on earth would they have hugged the coast, which is the most dangerous place to be?

From Mike Parker Pearson et al. 2015

The map appears to be a version of that shown by Parker Pearson et al. (2015, Figure 13) who suggest that the land route is most probable but nevertheless repeat the “long-distance sea route” which was first (as far as I know) proposed by Atkinson (1956, Fig.4).

Atkinson does show a route north from the Preseli Mountains and hence by sea around Pembrokeshire but favours instead a land route to Milford Haven because of the “very dangerous passage around the western peninsula of Pembrokeshire”.  The cliffs of the Atlantic coast of Devon and Cornwall, or the tide races at places like Portland Bill apparently posed no problem for him!  Atkinson favours a raft for use at sea, calculates its size, and decides the draft would be too great for use in rivers.  For that he shows a demonstration of three punt like boats fastened abeam (Atkinson 1956, Plate 22A).

Swallow Boats “Bronze age” model

The boat is not the problem:  Since the 1950’s there have been various demonstrations of the capability of “neolithic” boats to carry megaliths. While Seatern was being built, on my third visit to Swallow Boats I saw one moored in the Teifi estuary.  According to John (2018) this was  “Holgar” built by Swallow Boats for a 2012 Discovery Channel TV program. Pitts (2022) says he was part of the 12 man crew who paddled the 13m (43ft) Bronze age design “up a river”.

To me this all seems crazy!  It seems very probably that the neolithic people were capable of building and operating seaworthy craft, it is believed that they brought domesticated cattle from Europe (e.g. Cummings & Morris, 2018),  and spread neolithic culture along the west coasts of Brittany and the British Isles. This suggests that some of them would have been experienced small boat users. But faced with transporting some 40 or more stones each weighing lets say 1 to 2 tons (Abbott & Anderson-Whymark, 2012) by the sea routes suggested, and with the size of boats likely to have been available,  how would they have done it?  Could they have devised a workable “passage plan” for undertaking the voyages?

Need for a passage plan:  The maximum “hull speed” for a 45 foot boat is about 9 knots but you are unlikely to reach hull speed if paddling for some distance.  Looking at the Tidal Atlas (NP 256, 1992) on springs tidal streams in the Bristol channel go up to 4.5 knots, 2 to 3 knots off Pembrokeshire.  Local tide races will be more than that.  If you could build Stonehenge then you could have created harbours by building walls, but as far as I know no neolithic harbours have been found along the coast1.  So if you want to remain afloat, you are reliant on existing, natural harbours of refuge.  They exist, but they are widely spaced along the coast, and they lacked charts to tell them where the next one was, where there were hazards like tide races, and how strong the currents might be.  For all of that they would be relying on word of mouth.  Using the phases of the moon and local knowledge you can probably predict the direction of tidal streams, but the distances and paddling speeds mean that sometimes you will have to paddle against the current and go slowly, possibly losing ground.

And they had a major disadvantage;  they lacked good weather forecasts.  However experienced you are at observing the sky and watching coastal swells, that can only give you a short term forecast  To do a good forecast over a day or two ahead you need weather observations from a wide area which have been transmitted in real time.  They definitely did not have that. With a large number of rocks to transport and unable to maintain a speed greater than a few knots you are going to get caught out by the weather sooner or later, most probably sooner.  What this means that you need to be prepared to beach your vessel, possibly going through surf, to get out of a storm. Indeed, a major part of creating a passage plan is knowing what you are going to do if (and when!) things go wrong.

Accomplished seafarers like the Vikings knew this and built shallow draft double ended craft capable of being beached.  What about Neolithic people a 2 or 3 thousand years earlier, who are trying to transport some heavy stones?

If I was doing it in a boat like Holgar the last thing I would want sitting beside me would be a 2 ton rock!  Without the rock, in an emergency there would be a good chance of surviving a passage through moderate surf to run onto a sand or shingle beach and survive.  Many modern native fishermen land their open boats through surf.  If it all does go wrong there is a good chance that the crew will survive being tipped out and that the boat will be repairable.  But with a large rock in the boat, everything changes.  Driven ashore through surf the chances are that people will die and the boat be totally wrecked.

Tow the rock:  So if I had to go by sea I’d probably put the rock into one boat, or much more likely onto a raft, and tow it with two or three other boats.  Towing at sea would require a long tow to lessen the effect of the waves, and this would be particularly true if the towing boat is being paddled. Paddles provide intermittent power and this coupled with the surfing effect caused by the waves, means you need a long tow line to dampen the interaction between the towed and towing vessels.  Towing would only be practicable if neolithic people had long ropes.  If you have ever tried towing something at sea by paddling a canoe (or even using a boat with an engine) you will know that a long tow line is not just desirable, it is a necessity.

Whether neolithic people had long ropes is not known. Pitts (2022) has pointed out that previously proposed methods for raising the sarsens requiring long ropes would not have been practicable within the confines of the Stonehenge monument.  He describes other ways that they could be raised, so long ropes were not needed for that.  But methods proposed for moving the sarsens from West Woods on the Marleborough Downs to Stonehenge (assuming that’s where they came from), do envisage the use of long ropes.  A 1915 photograph of a megalith being dragged along a slipway of logs shows a very large number of people pulling on very long ropes (Pitts 2022, p.97) so perhaps that is circumstantial evidence that long ropes were available in Neolithic times, but we do not know.

Using a towed raft rather than a boat would make loading and unloading the stone much easier for transfer to land passages, and at sea it safeguards the stone from sinking. Rafts do not fill up with water like a boat. When reaching a natural harbour the raft can be anchored off shore ready for the onward journey. The towing craft can land ashore and the crew either camp on the beach or visit a local farm or village.  Having two or three towing boats means there are enough people to beach and re-float the individual craft.  With a long enough raft you could probably tow more than one rock since weight is not too much of a problem once the raft is moving.  Using a longer raft means the towing resistance is less, you would need it to be wide enough to be stable, but you would not be worried about the stones getting wet!  When the worst happens and you are driven ashore onto a beach through surf, the raft might survive, at least in a state that it might be repaired.  However if it were driven onto rocks, then you would have to go back for another stone; at least you would have been able to cut the tow loose and give yourself a chance of survival!

Go by land:  So towing increases the practicality of a sea route by increasing the number of potential landing places2, easing the logistics, and being safer in the event of being caught in a storm.  Did they do it that way?  I still think that any experienced neolithic boat user asked to transport 40 plus large stones, and having tried to formulate a passage plan, would have said “you’d be better off going by land”!  I’ll consider that next.

References

Abbott, M. and Anderson-Whymark, H. 2012. Stonehenge Laser Scan: Archaeological Analysis Report, English Heritage Research Report Series no. 32-2012, Appendix 1, Table 2.

Atkinson, R.J.C. 1956 Stonehenge, Penguin Books, 224pp.

Cummings, V. & Morris, J. (2018): Neolithic Explanations Revisited: Modelling the Arrival and Spread of Domesticated Cattle into Neolithic Britain, Environmental Archaeology, DOI: 10.1080/14614103.2018.1536498

NP 256, 1992. Admiralty Tidal Atlas – Irish Sea and Bristol Channel, Edition 4.

Parker Pearson, M. and 13 others, 2015. Craig Rhos-y-felin: a Welsh bluestone megalith quarry for Stonehenge. Antiquity  89 (348), 1331 – 1352.

Pitts, M. (2022) How to Build Stonehenge, Thames and Hudson, 240pp.

1 Harbours are needed if you have vessels which are too large to be beached and refloated. Lack of evidence for neolithic harbours might suggest that they did not have vessels much larger than, say, a 40 foot canoe.  You can land on a beach with domesticated cattle because, if need be, the cattle can be pushed overboard and allowed to swim ashore.  Rocks don’t do that.

2 As a modern comparison, if I decide to paddle a canoe or kayak around the coast there are a host of places I can land.  Indeed in a canoe or kayak, going along an unknown coast without having consulted a map or chart would be silly, but you’d probably get away with it.  In my 15 foot Seafly sailing dinghy I would have to be more careful, and in Seatern, which is a very small 20 foot yacht, more careful still.  But for either of those boats, if the worst came to the worst I could raise the centreboard and run up a beach. I might well damage the boat but I’d have a good chance of survival.  In a larger 40 foot fixed keel yacht I would definitely need to have planned things out ahead, the boat is more seaworthy, but you are limited where you can land.  And for all those boats, excepting perhaps a canoe or kayak, the most dangerous place to be is near the coast.