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
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.
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
2 – Sunday
Joined at HQ by Alice and Rhod. Then to the site and the digging
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.
site trench at the end of the day, viewing east along the Afon
Day 3 - Monday
Ian Cundy from Nautical Archaeological Society joined us this
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
backfilled, you would never know we had been there!
Day 4 - 9th
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).
and Rhod excavating the new trench, with Sue and Ian recording
the channel edge
trench over the bow showing the stempost and other timbers
Day 5 - Wednesday
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
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.
and profile drawing
remains of a bucket in the ship's hold
Day 6 - Thursday
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
bucket after cleaning
Day 7 - Friday
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
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