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Ynyslas Slate Hulk Investigation

Between 6th and 13th September 2014, Dyfed Archaeological Trust and the Nautical Archaeological Society will be undertaking investigations of an eroding wreck site on the bank of the Afon Leri.

The wreck is one of three in this area, which are all of similar size and shape.  They were probably locally built and may have formed part of the Derwenlas slate carrying fleet.  It is probable that they were deliberately scuttled in their present locations to mark the entrance to the Afon Leri channel for other seafarers.  They may have been scuttled in around 1868 having become redundant after the coming of the railway.  The importance of the three wrecks was recognised in 2012 when they were designated collectively as a Scheduled Ancient Monument.

The wreck site is suffering from erosion and was significantly affected during the winter storms of 2013-2014. 

It is proposed that partial excavation of the western side of the wreck (its bow) will be undertaken to determine its below ground survival, in order to create a record of what survives and determine how the scheduled site may be managed.  The work is experimental and we will try to develop a methodology to be used for future excavation and recording at the site.

The work is being funded by Cadw and with the support of Natural Resources Wales.

Day 1 – Saturday 6 September 2014

No excavation work today, but a quick visit to the site to check the tides, locate the position of the trench and visit the Nature Reserve centre to erect a small display. Following that it was a quiet evening establishing our headquarters in Borth.

The site area before excavation commences

Evening sunset at HQ

Day 2 – Sunday 7 September

Joined at HQ by Alice and Rhod. Then to the site and the digging commences.

The site area is muddy and slippery on the surface, but the estuarine silts and sands are easy to cut through. It does not take long to realise that the soil is heavy, so by the end of the day we have a large spoil heap, a small trench and very tired arms. Unfortunately we have revealed no remains of the wreck today – so it lies deeper in the mud.  Another day of hard work awaits tomorrow. We cannot complain though, the setting of the site is beautiful, the weather is fantastic and we even had a diving display by an Osprey.

Muddy conditions

The site trench at the end of the day, viewing east along the Afon Dovey

Day 3 - Monday 8 September

Ian Cundy from Nautical Archaeological Society joined us this morning.

Job one, bail out the trench.

Job two, do some highly technical probing through the silts to determine the depths of the timbers.

There is no sign of any timbers within our trench.  We move to the south and start to find them buried quite deeply around 1m from the end of the trench.

We then proceed to determine the outline of the wreck, which is some 4m shorter than we had anticipated. Our trench has missed the boat (ho ho).

Alice, Rhod and I spend the rest of the day backfilling the trench we dug yesterday, the soil being twice as heavy due to waterlogging.

Back to the drawing board!

Emptying our muddy eternity pool

Trench backfilled, you would never know we had been there!

Day 4 - 9th September 2014

Today we were joined by Sue Barker of NAS. 

Ian and Sue undertook a survey of the present river channel edge to monitor the rate of erosion of the bank around the wreck site. It seems to be eroding at a rate of around 0.4m a year, but is greater in some areas as scouring occurs on either side of the boat. Later in the day they undertook a probing exercise over the second of the three wrecks – which indicated it lies at a shallow depth  below the silts and may still have its deck relatively intact. We had a site meeting with Cadw, RCAHMW and NRW to check on progress and discuss initial ideas for recording strategies and longer term management of the wreck.

Alice and Rhod excavated a smaller trench over the suspected area of the bow of the boat. Happily this trench did confirm the presence of timbers. The exposed timbers suggest they are the stempost, possible apron and stemson. We also recorded a measured profile across the buried part of the boat, which worked quite successfully so that we shall do more across its width and length tomorrow. Following a rapid recording exercise late in the afternoon we backfilled the trench over the bow in double quick time to beat the very quick incoming tide and safely made it off site just in time to catch the ice cream van as it was leaving the beach (which was very welcome).

Alice and Rhod excavating the new trench, with Sue and Ian recording the channel edge

The trench over the bow showing the stempost and other timbers

Ice cream selfie…

Day 5 - Wednesday 10th September

We were joined by Hubert from DAT today to survey the site.  We surveyed as many of the exposed timbers of the wreck as we could without risking damaging the vessel or of course falling in the Afon Leri!

Alice and Rhod recorded more profiles of the depths of the boat timbers and then commenced a more detailed photo survey of the wreck and objects within it.

Ian and Sue completed the probing survey of wreck 2, confirming its extent.  This has shown that it was the smallest of the three wreck sites, although clearly seems to be the best preserved.

Hubert and I also surveyed as much as we could of the other two wreck sites and then located everything in relation to features recorded on Ordnance Survey maps.  Not as easy as it sounds as the wrecks lie so far from any such features!   A very successful day though.

Surveying and profile drawing

The remains of a bucket in the ship's hold

Day 6 - Thursday 11th September

A bit of extra excitement today as we had reported a possible piece of ordnance on the bank of the Afon Leri.

This has prevented us from doing any more on the middle wreck whilst the object is dealt with.

We spent the day working on the main wreck site, recording in more detail some of the features and objects on its surface, including the bucket and parts of a small wooden box. We found a short length of rope beneath the bucket which was very well preserved.

Ian and I showing the Borth coastguards the possible piece of ordnance

The bucket after cleaning

Day 7 - Friday 12th September

Most of today was spent waiting for the site area to be made safe by the Royal Navy Bomb Disposal Squad.

We had mentioned to them that there was a piece of metalwork on the wreck that also looked suspicious, which they confirmed was also a piece of ordnance and would need to be made safe with a controlled explosion.  At  this point I became a little nervous, partly as we had been working next to the object all week, but also as I was worried that on our final day, the final act might have been exploding the wreck!  At around 5.00pm a controlled explosion dealt with the objects, and we were all quite shocked as to how loud it was (no photos allowed…).  Luckily they had placed all of the objects in an area safely away from all of the wreck sites.

Once cleared, we were allowed back to the wreck, although we did so somewhat nervously to begin with.  We took some final photos of all the wrecks, but did no more digging or probing, just in case.

Overall the week has been a success, although we didn't manage to find a name plate for the vessel and so confirm where it was made, we have been able to determine its surviving width and length and establish that it was carrying slate on board from the few broken fragments we recovered from the hold.  We have removed and temporarily stored the remains of the wooden bucket and the pieces of a small wooden box, both of which would have been washed away before the end of the year.  The information can be used to develop ways of dealing with the site in the future and determine the success or otherwise of some of our recording methodologies.  Through the NAS and our survey we have established the size of the surviving parts of the middle wreck site which although may be the smallest, appears to be the best preserved.  Through the information we placed in the Nature Reserve visitor centre and talking to members of the public we have made more people aware of the sites as well.  And of course we managed to get some ordnance made safe without harming the wreck sites!

The exposed timbers of the northern wreck

A last look at the eroding wreck

Farewell to the site, for now




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