Tim Kirk’s Shipwright’s report for March

As we continue the behind-the-scenes planning to return to working in the Longshed we have, at last, been able to commence preparatory work on the timbers for the backbone of the ship.

Some time ago we took the decision to saw blanks for the keel and posts (from the logs that were delivered in January).  We have made up a ladder to guide the first cut of the chainsaw mill, to avoid wasting the valuable resource that these logs represent.

ladder for the chainsaw mill

The keel log will be cut at the beginning of April and transported to the Longshed so that it can be shaped and finished with axes.

The curved log for the ‘underloute’ and lower stems will get the same treatment.  Fitting patterns from the lofting that we did earlier shows that this log is as near a perfect fit as could be wished for.

When all these parts are in the Longshed we will truly be able to say that the actual build of the ship has begun.

Tim Kirk March 2021

The Other Team on “The Dig” – Joe Startin

The film “The Dig” understandably focuses on the team Charles Phillips put together to handle the burial chamber and its contents.  It omits the team he organised to survey the ship.

Phillips first met Mrs Pretty, at Sutton Hoo, on 6 June 1939.  He made phone calls on her behalf to the British Museum and to the government (the Office of Works) that day.  The government formally asked him to take over the excavation project at the end of June.

The survey team was led by Lieut-Commander J K D Hutchinson, aged 38, married with no children, the Keeper of the Department of Ship Models at the Science Museum and a retired naval officer.  His second, also from the museum, was A S Crosley, aged 45 or 46, with (from research by Dr Caryl Dane) at least three daughters up to the age of 10.  Crosley was an active member of the Newcomen Society and presented a paper about the ship to them in 1943.  The other member of the team was young Frank Gillman.

Hutchinson first visited the excavation site at Sutton Hoo on 12 July 1939,  the day before serious work began on the burial chamber.  After an inspection, he explained to Mrs Pretty what a survey of the ship would require, and she agreed to his proposals.  On the afternoon of Tuesday 8 August the team of three arrived and “…..orders were given in Woodbridge for the construction of the necessary wooden apparatus for the survey”.  This was one week after the work on the burial chamber had finished.

Mercie Lack and Barbara Wagstaff also arrived on 8 August. They were on holiday in the area.  Schoolmistresses and companions, they were very capable photographers with good equipment.  They made an invaluable record, and were among the last excavators to leave, on 25 August.

In his Newcomen Society paper, Crosley describes how the survey team measured the positions of certain rivets  near each rib, relative to a datum line with plumb bobs hanging from it.  This was a laborious three-man operation.  Where that approach was not practicable, at the bow and stern, measurements and sketches were made from a bosun’s chair suspended above the excavation.  Southampton University used this data as the basis of research to derive the plan that SHSC are using to reconstruct the Ship.

Hutchinson and Phillips seem to have got on well.  Hutchinson took charge of most of the work at the site, while Phillips “was able to consider the problems of the ship at leisure and discuss them with Commander Hutchinson”.  

They pursued a number of investigations together – into the keel, for example, and how it connected to the stem and sternpost.

Hutchinson’s signature can be seen on the legend for a tracing of the 1939 ‘provisional drawing’ done by Crosley – which can be seen in Ipswich Museum

Hutchinson died ‘of illness’ in July 1944.  He was Acting Commander of HMS President, which I believe was a training establishment on the lower Thames.  All his papers were burnt by his widow.

It was said that Crosley and Gillman did not like him.  Perhaps he was a hidebound officer who rather stood on ceremony.  At the end of his paper, Crosley says: “I thank the Director of the Science Museum for having allowed me to undertake this interesting survey and for permission to publish the results.  In making the survey I would like to put on record the valuable help given by my colleagues, Messrs. Gillman and [John] Jacob, who showed untiring energy under difficult conditions.”   There is a notable omission…

Joe Startin

 

 

An Experience of Photogrammetry by Andy Spencer

It is important for SHSC to have a scientific record of the components of the ship, as part of our experimental archaeology programme.  As things progress, we need to be able to look back at the materials we used and what we did. Photogrammetry is the science of creating a three dimensional model from a series of standard two dimensional photographs.  It is clearly the right thing for us to do.

What I have learned so far is that photogrammetry can be tricky!

I was already involved in The Ship’s Company as a volunteer, and as someone with an interest in photography starting off the photogrammetry project played to my strengths.  In an initial meeting a group of interested volunteers discussed the use of photogrammetry to create 3D models of the ship, its parts and the tools we would use in constructing it.  Subsequently we were kindly given access (by Felix Pedrotti of Southampton University) to some online tutorials  about using software and how to upload and convert the images into a 3D model.  I also did some research online and contacted Julian Whitewright for advice (there is a profile of Julian in the February 2021 newsletter).

Most people would choose to start with something relatively small that could be photographed under ideal conditions – like the clamp shown at the top of this post. However, we decided that the first photogrammetry project for the SHSC records should be the log that will form the keel of the ship. The keel log is 13 metres long and currently stored in a poorly lit barn.  Our project was no small task!

In January, fellow volunteer David Keeble and I made our first attempt to record the keel log and a second log that will be used for the stem and stern.  We had to decide on the section to be covered in each picture, and on how many to take down the length of the whole log.  There would need to be a large enough overlap in each picture so that the software creating the 3D image can work out how each picture sits in relation to the next – and from that build a 3D model.  Clever software!

We marked out locations about a metre apart with white tape down the length of each log , and about the same distance from the sides. We decided that three photographs would be needed at each location: close to the floor, about 75cm above the floor and looking down onto the log as close to vertically as possible.

The image below shows the plan that I sent Julian for advice on the angles we needed to cover.

On Julian’s advice we set more locations for pictures to be taken from each end of the log that would help the software interpret the images.  So we marked 36 locations around each log and took three pictures from each one, starting off at the lower level and then going round the entire log again at the second and third heights.

The right levels of light are important so it was challenging at times – low light levels meant long exposures and in places we had to use extra lighting but too bright a light also causes problems. We ended up with 216 carefully taken photographs!

We sent all the images of to Julian to upload using the Agisoft computer programme at Southampton University.  But after all the our efforts the software couldn’t create a 3D model.  We needed even more pictures, especially at the ends and from the top.

So, we are going back to try again with more lights.  I will fix the lens on the camera so that the zoom doesn’t change and we will need to work out the maximum possible distance that we can get from the trunk where space is limited.  Hopefully second time lucky!

The photo below and video link show how well the technique can work.

Andy Spencer

R2 D2, an exercise in photogrammetry by David Matzliach

Joe Startin Speculates, ‘Did the Sutton Hoo Ship Sail?’ (Part 4)

This is the fourth in Joe’s series of speculative posts – click here for links to parts 1, 2 and 3  

Edwin Gifford built a half-length replica of the Sutton Hoo ship in 1993 – Sæ Wylfing (moored outside the Longshed in the photo above).  He was fed up with people saying that the shape of the hull meant that it could not sail in much the same way as the classic Viking ships.

He was not seeking authenticity in materials, building techniques, and so on, but he did take care over the shape of the hull. The weight of Sæ Wylfing is 675 kg. Crudely, you would then expect the full-size ship to weigh 2 x 2 x 2 = 8 times this, or nearly five and a half tonnes. The hull and the ribs of the reconstructed ship are indeed expected to come close to this, but the thwarts, other internal supports, and a deck will add further weight.  Actually we are expecting it to weigh in at about 9 tonnes.

And of course he rigged a mast, and a yard and a sail to go up it.

Gifford gave the central thwart a thicker support in the middle, and some reinforcement where the front of the mast pushed against it.  In the image below, down between the oars you can see a lengthways member, with a recess in it. This is called a keelson, and the hole is a mast step, where the bottom of the mast fits. The main force the mast exerts on the hull is downwards, and the job of the keelson is to distribute this.

Gifford recounts some of the adventures he had in Sae Wylfing between 1993 and 1995. All the pictures show him at the helm, and I suspect this was always the case. He made some small additions to the keel in the winter of 1993/4. In 1994, when he was double-reefed in a wind gusting to 22 knots, he found he could make no progress to windward. He “decided to lower mast, first time afloat, and row.” This must have been terrifying. The dedication and composure of his crew was admirable.

His best result sailing to windward was at the Maldon Festival in 1995.

“…we covered three nautical miles direct to windward in 3.5 hours, despite many short tacks and loss of ground in crowded anchorages.”

This is just under one knot for ‘course made good’. For a land lubber that’s about one mile an hour.  And the effort of enforced tacks would have been a huge task for the crew.

The full-size reconstructed ship will be eight times as big as Sae Wylfing….Rowing (and paddling) it will be our priority. The first trials will be on the Deben; then the time will come to cross the bar and go out to sea.

Sae Wylfing on the Deben 2019

When the trials in a seaway are complete, and the ship is much better understood, we can explore how the hull performs with a big sail and the wind from the side.

Joe Startin

Tim Kirk’s Shipwright’s Report for February

This month progress on the build has been very limited because of lockdown restrictions.  This report is about essential work that we are doing to source wood for the hull, frame and oars that will make the ship a strong, seaworthy vessel.

Readers of previous posts will know that we already have already obtained a straight grained oak log for the keel and another fine one to begin forming the curved ends of the ship.  Most of the rest of the timber needed for the hull is in two forms:

  • long clear runs of oak from trunks 6 metres to 9 metres in length and up to 1.2 metres diameter for planking and other longitudinal timbers, and
  • curved timbers up to 4 metres long and 0.4 metres diameters for frames or ribs

We will also need multiple smaller sections.

Oak for planking and longitudinal members must be straight-grained and clear of knots, shakes and other defects.   The twist in planks from trees that have grown with twisted grain (shown by spiralling of the bark fissures around the trunk) is not acceptable for constructing most of the ship.  But we do need just one length of timber with a twisted grain, about 6 metres long and 0.9 metres in diameter for the end pieces of the lower planks.

Twisted grain in a cleaved log

The framing of the ship is built up from multiple pieces of curved timber:

  • floors, which cross the centreline and provide much of the transverse strength
  • futtocks, which attach to the floors and frame sides of the ship; and
  • rongs, which combine a floor and a futtock.

Combinations of these frame sections, regularly interspersed along the length of the ship, minimise the weaknesses caused by scarfed joints and maximise the athwartship strength.

These timbers, made from curved trunks, or larger branches from the lower canopy of the tree, need to be up to 3 metres long and 0.5 metres diameter.  For strength, ideally we need to avoid using the central ‘pith’ and the outer ‘sapwood’.  However, there is some archaeological evidence from other ships that both the centre of branches and sapwood might sometimes have been used.

The key requirement to maximise strength is that the curvature of the grain in the frames meets the natural curve of the ship. This means that we have to place individual full-size patterns against the timber that we are planning to use to assess whether it is suitable.

The photo on the left below shows a frame section fitted to our full-scale model of the ship.  The softwood molds in the background are temporary. The drawing on the right shows the different frame sections and their placement within the ship.

We need larger curved sections to form the stem and the sternpost .  We already have one suitable trunk but we will need at least one more – up to 6 metres long.  The trunk in the photos below (shown standing and felled|) is 10.8 metres long and 0.9 metres diameter – big enough to obtain two pieces, one from either half of each length of timber.

We have made full-size patterns to test against potentially suitable trees.  We hope to find a group of suitable trees on one site as this would save time and reduce the costs of transport.

Other, smaller curved pieces will come from smaller branches in tree canopies.  This sort of timber isn’t easy to obtain as it is not commercial for timber yards and is often cut up for firewood.  The photo on the left below shows grown a ‘crook’ , needed for the end frames of the ship, and on the right a branch junction that will be used for making ‘tholes’ (where the oars pivot on the gunwale of the ship).

We need about fifty sections like these – each about 1.2 metres long and 0.3 metres diameter.

Oars – we will need about sixty in total, including spares and different experimental designs.  Although tholes (primitive rowlocks) were identifiable in the Sutton Hoo Ship excavations there was no evidence of oars. We have found out as much as possible about what the original oars might have looked like but there is a lot to be done on shape, weight and pivot points. This is a case where experimental archaeology comes into its own – all these issues will be covered in detail in a future research paper.

Initially we will trial different materials – oak, ash and scots pine – making about six of each type. The timber for oars needs to be straight sections about 6 metres by 0.2 metres with no knots or other defects.  Larger diameter timber could be used to make several oars from each trunk. Once we make a final decision on what sort of trees to use we will need enough wood for forty oars.

Other parts of the ship will come from offcuts of the larger sections.

We expect to use the equivalent of around twelve mature oak trees to build the ship.  Although this will undoubtedly require more than twelve trees to be felled one of our key targets is to replace each tree we use with ten saplings.

Tim Kirk, Master Shipwright

 

 

Shipwright’s report – January 2021 – Tim Kirk

Unfortunately, lockdown has again slowed our progress.  However with the arrival of two logs for the backbone we are in a good position finally to begin the build of the Ship as restrictions ease.

We have lofted (drawn full scale) the stem and stern posts which will enable new patterns to be taken for the underlouts (between the main keel and stem/stern).  The sections of the stem and sternpost and the logs for the keel can be rough sawn before delivery into the Longshed for final finishing.  At present, we aim to complete the stem and stern posts in two pieces – as shown in the photo below of the model that I made.

Image showing detached upper sternpost and lower sternpost attached to underlout

Because of the size of the posts (some 6m long and 300mm square in section before shaping) it isn’t easy to find exact curves on a log of suitable quality.

Hopefully this will all happen around Easter time.  In the meantime, stay safe and sharpen your axes.

Tim Kirk

Joe Startin speculates – did the Sutton Hoo Ship ever sail – part 2

Did the Sutton Hoo ship ever sport a hefty mast and a big sail? It would help if we knew what the ship was used for.

An expert view is that it could have been a sort of royal barge, a means for the king to project his power and majesty throughout much of his domain.

Raedwald (Julian Illman) in the 2017 production of The King’s River

One’s subjects should be clear about who is protecting them, and who they must pay their taxes to.

As king, it is a good idea to put oneself about and let oneself be seen. But travel overland with a large entourage would have been excruciating. Much of the populace would have lived in settlements up the estuaries, creeks and rivers which permeated East Anglia.

Using a large ship of shallow draft would be a practical alternative. Your bodyguard could show their devotion by rowing you wherever you needed to go.

The coastline would have been quite different then. Land reclamation had not begun. There would have been much more inland water about (particularly when the tide came in.)

Coastline in the area of Sutton Hoo. Modern coastline in feint, bold coastline follows 10 ft. contour. Crosses show sites of medieval churches. Based on an idea by George Arnott. (Drawing: Martin Carver)

A sail would be of limited use when you were winding up and down the rivers. Your oars can shift you in any direction whenever it suits you.

Moving from one river entrance to another would require a passage along the coast. The extra sea-room might allow and encourage the effective use of a big sail. Unfortunately, a large mast does no good for your rowing. The experience of a comparable Viking ship reconstruction was that you would lose a knot because of the windage on it. It would be soul-destroying for your oarsmen if you kept the mast up all the time, but rarely used it. But taking it down while on the water, or putting it up again, would be very risky.

The two photos below show boats with masts being rowed – not difficult in very calm water with no wind against you.  It is also easier if like the Faroese boat on the right, the craft is designed to be dual purpose and your crew has experience of both sailing and rowing.

If you do have a following wind, and you do not have a big sail, all is not lost. The rowers can take a respite simply by holding out their oars. Better still, the skipper could deploy some sort of temporary rig, with a small sail – something quick to raise, and easy to stow away again. This would not be proper sailing of course, but for the oarsmen it would be a blessed relief.

None of this is to say the ship could not sail properly. It is just a way of wondering whether it was worth the bother.

 

To be continued…

 

 

Damian Goodburn’s Holly Maul

Google “maul” and you will get a variety of definitions, like being clawed by a lion or clashing on the rugby field. The Merriam-Webster dictionary is the first one I looked at that defined a maul in the sense we are using it – a heavy often wooden headed hammer – which is what we asked Damian Goodburn, a very experienced user of a special version of this tool, to tell us about.  All of us in SHSC have admired Damian’s own very special maul.

First of all, he added to the definition “Single piece mauls or mells are still used by some green woodworkers and hedge layers.   They are generally stronger than those with separate handles and heads and this allows the handle shaft to be of thinner dimensions, which absorbs shock better than the modern separate timber handle.”

Well, how on earth can you get a hammer made from a single piece of wood? Of course, Damian has the answer

“Any tough species of timber can be used  where a branch stem junction is the right shape, but if the large striking head is made of a knotty section of the main tree stem then it will last all the better.” And he knows, from experience “In my holly example the knots act as bolts holding the timber together, so it resists splitting for a long period of use. Holly is also a very hard wood and many of the branches join the main stem at about 90 degrees, just right for the job.  My example is well over 20 years old and has been used for driving wooden wedges to cleave logs and driving fence stakes etc regularly during all that time.  It still has some life left in it yet!” 

And he ain’t just pussyfooting – “The largest log split using the maul was c. 1.2m diameter,  of oak and used for making the pair of bottom planks for the research and display hull section replica of the Dover Middle Bronze Age boat.” 

The replica of the Bronze Age Dover boat

That seems particularly apposite because, he goes on to say – “The oldest single piece maul we have in British archaeology is an early Bronze Age example of Yew from the Somerset levels.”  

Damian has recently been in action with his 20 year old maul  “Most recently it was used to cleave a moderately large ash log at the Weald and Downland Museum  in W Sussex during  two weekends of demonstrating aspects of Saxon woodworking or ‘treewrighting’  in early September”

Damian’s holly hammer is still going strong – this photo was taken in September 2020. Damian in the background, Alex Blanks (archaeologist) with the hammer

I hope we aren’t still going to need to be using the SHSC holly mauls in 20 years time – at least not on the current project!

Shipwright’s report – December 2020

As the year comes to a close we are back in the Longshed and continuing to make progress, with restricted numbers of volunteers.

Whilst we wait for delivery of the keel logs we have lofted the design stations of the hull to full-size (that means drawn out full scale plans) and begun making molds to control the shape of the hull whilst it is in build.   Although the Anglo-Saxons would not, we think, have used molds, we need to speed up the build to make up for time lost to Covid.  It won’t affect the authenticity of the completed ship, nor the sea trials following.  And once they are set up on the keel the molds will give an immediate impression of the size of the ship to Longshed visitors.  If we are able to continue at pace, then the molds will be removed once the lower half of the planking and framing has been fitted.  We will then complete the build using wholly traditional techniques.

lofting and frames
Lofting and frames

The midships model continues to be fitted out with three floors – the bottom, central parts of the transverse framing – fitted and about to be fastened up. Who knew that such little things like trenails could be so complicated to make and fit!

Jacq Barnard and Jules Hudson demonstrating the benefits of having a floor in the midships model to test rowing positions

We are producing another oar from the ash received in March.  Hopefully this will lead to something of a production line being set up – we are going to need fifty or so in total. There is work for lots of different people here.

Thank you again to all of you who have been able to work with us this year and  for the patience and forbearance of those who have not been able to; hopefully, by the Spring we will be able to see a much clearer way forward.

Wishing you all a Happy Christmas

Tim

Shipwright’s report – Tim Kirk

12 foot midships model

Since we returned to operations in the Longshed at the beginning of August we have continued training and preparation to begin the actual build of the ship.  Covid has restricted numbers working but we have been able to plank the lower half of the midships model on the port side, using oak from the ‘twisted’ log that we took delivery of in autumn 2019.  Jo Wood, David Turner and Dave Rowley completed the work, including testing two caulking methods – both known to have been used in Anglo-Saxon and Viking period ships. Both methods worked equally well, providing us with something of a conundrum as to which to apply in the ship.

A different team will complete the planking in order to broaden the skill-base within the Ship’s Crew.

The starboard side has been completed in mock-up by Mike Pratt and David Steptoe, using plywood and softwoods.  We are getting on with that so that we can begin the experimental part of the project – investigating the bio-mechanics of rowing the ship. Nothing is known of the internal structure and the rowing positions will have to be derived from various technical procedures.  Jacq Barnard is involving specialists from British Rowing to advise on this aspect of the build.

Oars

We now have one (prototype) oar, made using modern techniques from the ash received last spring from Suffolk Wildlife Trust.  We had to use power tools to shape this oar because the wood had seasoned, and hardened, during the lockdown.   Still, it is a work of art – thank you Simon Charlesworth.  Brian Hunt is constructing a second oar.

Keel and strakes

We have laid a false floor in the Longshed to rest the 12 metre keel log on, in preparation for working it and subsequent cleaving of the garboard strakes (the first planks of the hull).  We will work on the second, curved, log for the stem and stern and keel ends at a new site located at Hoo House Farm (a few miles from Woodbridge).  We have temporary use of a barn similar in size to the Longshed and much of the initial cutting and cleaving of logs will be done there.  We will bring the semi-finished components into to the Longshed for final finishing and assembly.

The supports and false floor ready for the keel log
1:5 model

This model is really important as a source of practical information for the full-size build.  John Cannon and Clive Cartmel have completed battening-out of the planking.  Doing so has raised issues with the layout of the planking – that’s one of the next problems to be solved.  But its much better to identify issues like that now than when we are working on the shipbuild with hefty full-size planks five times as big.

The 1:5 model battened up for planking

Next…

Research continues; very little information exists about Saxon-era anchors and mooring systems.  Vicky Fleming has written a very stimulating research paper on the subject.  Joe Startin continues to lead on our research and has gleaned nuggets of information from the folk at Nydam in Denmark.  I am excited to be writing the dissertation for my degree on the development of the side-rudder, with particular reference of the Sutton Hoo Ship.

The next stages of the build will focus on the conversion of the keel and its extensions (the ‘underlouts’), lofting of the sections of the ship and making the moulds to check the accuracy of the shape as we build.

Many thanks to all those involved and we hope that as we go forward we will again be able to involve more people in the build team. Apologies to anyone whose contribution has not been acknowledged – I really value all the contributions that you make.

Tim Kirk, Shipwright 5:11:20