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

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

 

 

Arrival of our keel log!

It’s here.  We have a the keel log we have been waiting for!

What a story of suspense, from first identifying the tree in a Forestry England site in Wiltshire nearly a year ago, through delays in felling, postponements because of Covid, a carrier who failed to bring back the goods, to finally manoeuvring the artic into the shed and then craning off the logs.

The log – or logs, for as well as the straight part of the keel we have the curved one for the two ends of the ship – are now safely ensconced in a barn near Woodbridge where the team will be able, soon, to do preparatory work before we bring them to the Longshed, hopefully to great fanfares.  Even without fanfares, the arrival at the barn was really quite special.  A huge articulated truck complete with (very necessary) accommodation in the cab rolled up one damp chilly January morning, into a giant barn.

Brian Amos, the driver, had been on the road the day before and spent the night in a lay by south of Woodbridge. He demonstrated great skill in manipulating the huge logs off the trailer; the barn owner observed that at one point the apex of the crane was within 15cm of the barn roof but both logs were quickly manoeuvred with pin point precision onto the waiting supports.

 

This was an occasion where practicality ruled out any attempt at Anglo-Saxon authenticity! Perhaps their log movements would have been more like the description of a nineteenth century timber delivery in this extract from Thomas Hardy’s The Woodlanders

The proud trunks were taken up from the silent spot which had known them through the buddings and sheddings of their growth for the foregoing hundred years; chained down like slaves to a heavy timber carriage with enormous red wheels, and four of the most powerful of Melbury’s horses were harnessed in front to draw them.

The horses wore their bells that day.  There were sixteen to the team, carried on a frame above each animal’s shoulders, and tuned to scale, so as to form two octaves, running from the highest note on the right or off-side of the leader to the lowest on the left or near-side of the shaft-horse.  Melbury was among the last to retain horse-bells in that neighbourhood; for, living at Little Hintock, where the lanes yet remained as narrow as before the days of turnpike roads, these sound-signals were still as useful to him and his neighbours as they had ever been in former times.  Much backing was saved in the course of a year by the warning notes they cast ahead; moreover, the tones of all the teams in the district being known to the carters of each, they could tell a long way off on a dark night whether they were about to encounter friends or strangers.

Philip Leech

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

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 – 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

 

Reflections on creating the keel for our ship

Building this great ship starts with construction of the keel.  What did we need to look for when identifying suitable trees?

The key point is that finding a straight, and nearly flawless, oak for the thin plank keel is a huge challenge in England today as we have no wildwood.  Damian Goodburn advised that “Even in early Anglo-Saxon times after intensive Roman use of the woodlands for 350 years this would have been a big challenge.  It might have been easier later once the wildwood spread out further, until the 13th century in southern England.”

A deeper section of keel that could accommodate some knots would make the challenge a little easier, but this is not an option.  That’s because we are constructing a ship that does not just exist in the Shipwright’s head.  Our aim is to build a ship that is as near as possible to the original ship that was buried at Sutton Hoo, and we are working to a plan that’s based on what was found in the burial mound. The evidence from the burial mound is that the original ship had the shallowest keel imaginable, as you can see from this cross section of a (rather smart) model that Damian made for the original exhibition at Sutton Hoo.

Photo of the model made for the NT exhibition at Sutton Hoo showing the T shaped keel section

The keel is the T shaped section in the middle of this photo.  It is a slight thing, but it beautifully reflects the evolution of shipbuilding, from rafts, through hollowed-out logs, to hollowed out logs with planks attached at the sides to deepen the vessel, to a plank as the keel…  The keel may be slight but it is a lot more sophisticated and allows the ship to grounded without damage.  What extra strength it has over a plank isn’t clear – our ship probably flexed a good deal.  The strength to keep its shape also came from the thwarts – 26 cross pieces that it was probably possible to sit on whilst rowing.

Our keel hunters have found a beautiful, straight grained and knot free tree.  Although finding something in southern England long enough didn’t seem likely at one stage.  Even so, whilst the keel needs to be straight, the stem and stern just aren’t.  Luckily we also found a tree with a curved trunk that looks like it will fit the bill.   Damian has provided a practical solution as to what to do to make the best of our lovely straight log and the curved one as well.

“I suggest that the practice attested in later Viking longships and later medieval clinker vessels be uses, that is a keel with two linking pieces – ‘lots’ or ‘underlouts’, and stems above each underlout.  That is the main keel of about 10-11 metres with enough for scarfs each end be scarfed to more ‘v’ shaped and curved underlouts at each end about 6 metres long which are then also scarfed to the main upper stem timbers above them around 6.5 metres long.  This approach could be adapted to the actual timber obtained and adjusted as  required – though symmetry was likely.  The scarf locations would also be bridged by garboards and other bottom planking.”

For those who aren’t boatbuilders or maritime archaeologists, this means:  at the end of the straight bit of keel under the ship, the gentle curve upwards is produced by joining the keel first to one (underlout) then another, curved piece.  The overlapping joints at the end of the keel and between the two curved bits are the scarfs – as you can see the scarf joint at point F in the photo below.

This image showing an imagined scarf joint (point F) is from drawings made in 1975 following the second excavation of the burial mound. (If the scarf had been made this way round it could have ripped open when the boat grounded)

And the garboards are the first planks that make up the bottom, then the sides of the vessel.  You can see them in the first photograph (of Damian’s model).

Damian again: “All the parent timbers found have to be cut out well over length ie 12-14 metres for the keel and about 7 metres, with appropriate curves, including scarfs for the underlout and stem logs.  As the late Saxon Graveney boat has a stern post made from half a log and this – two stems from one curved log approach – was widely used in practice in later medieval vessels, I would suggest that each selected log be divided in two, length-ways, by sawing and then hewn into shape with Saxon style axes.”

There is an element of revolution in that advice.  Damian is suggesting that we use saws for some of the processes and finish the work with traditional hand tools.  The heresy is to saw the logs but he makes the suggestion with good reason:

“The Anglo-Saxons did not have saws of any size.  But I personally think that splitting the log for the keel is unrealistic and could be enormously time consuming as defects in the chosen log’s grain might make each log half unusable and in large timbers the defects could be hidden inside the parent logs until too late.  Roskilde (our colleagues at the Viking Ship Museum in Denmark) have already shown that this is a perennial problem for keels and stems in early clinker vessels that are made without any sawing length-ways.”

So the point is, that you could do a huge amount of work and up with a keel shaped piece of wood that is totally unfit for purpose and in essence wasted.  A whole oak gone for nothing.  We cannot risk that.  Following Damian’s advice we will record the sawing for display and publication as a technical compromise.  Shaping the best keel slab with Anglo-Saxon tools will still be a great spectacle and a huge challenge.

So, how do we think that using a non-traditional method as part of the construction affects the project?  Is it still and authentic reception of the Sutton Hoo King’s Ship?  Our overwhelming answer is – yes, it will still be authentic.  Using sawn timber to construct the keel will not affect the weight, the strength or the appearance of the ship, and very importantly, will not impact on the validity of sea trials.  It will reduce time and expense, as well as probably saving us from wasting trees.  There are other obvious compromises that we have already accepted: did the Anglo-Saxons build indoors on a concrete floor?  Did the fell their trees with chain saws?  Were their labourers volunteers, and did they have protective equipment?

We can’t conceive of all the problems that the Anglo-Saxons overcame in building their King’s Ship.   Adopting the practical compromises that we are choosing to make just leaves us all the more in awe of what they achieved.

 

 

Why are we using green oak to build the Ship?

We often get asked why we are using green oak to build the Ship and why we are (where practicable) using ancient techniques.  Here, Dr Damian Goodburn who knows much, much more about medieval oak than most people,  provides us with many reasons why we should do so.  The photo above shows Damian using a side axe.

“Simply put, green logs and roughed out timbers are very, very much easier to work with human muscles than partially, or totally seasoned timbers – especially using simple hand tools, such as axes.  This is probably principally why it was used in such a green state.  And there is much evidence for the use of green timber in the early medieval period for ship building (including from Sutton Hoo and large scale woodwork elsewhere) – and no evidence against it.

Experiment and experience shows that if the surfaces of the timber are worked green an axe-finished surface is smooth with little or no tearing of the grain, with widely spaced axe marks.  Well-preserved surfaces on early medieval boat timbers and other heavy woodwork show a smoothness that would fit with this. The impression that the Sutton Hoo Ship left in the ground was entirely smooth.  Where second-hand seasoned timbers are re-used and refinished, because of the comparative hardness of dry oak the tool marks are much rougher and closer together.

Fragment of the Bayeux Tapestry, with edging, showing the construction of ships for William the Conqueror. (Classic image/Alamy Stock photo)

Historical sources from the end of the early medieval period, and images such as the Bayeux tapestry, and other embroidery, show that timber was worked on in the woods where it was felled.  This implies rapid, green roughing out at the very least.

Later medieval ship and boatyard excavations also show roughed out timbers arrived in the yards in freshly felled condition with some work having been done at the felling sites.  The lack of drying shakes (cracks running through the timber) or any marked decay supports this – though in a few cases there was also some re-use of second-hand timber taken from earlier vessels.

Systematic tree ring dating studies of early medieval woodwork and boat timbers (all a little later than the ship burial at Sutton Hoo) show very little evidence of stock piling timbers for seasoning.  Where we do have historical dates for medieval buildings and vessels made largely or entirely of oak, for the vast majority of timbers evidence from tree-rings shows that felling was usually only shortly before the recorded date of construction.

A quick turnaround – using green rather than seasoned oak – has benefits from an economic perspective, and to avoid timber degradation from drying shakes, rot or insect decay.  Degradation is less problematic when timbers are worked into smaller sections.

In reality the terms seasoned versus green are rather misleading extremes, even today.  We might accept oak as ‘seasoned’ when moisture content is down to about 20%  or less, whereas green oak has much more moisture-sap in it.  In the early medieval period totally seasoned timber (other than second hand material) is likely to have been a rarity and for use in small high status items.

Wet storage inhibits decay and slows down any hardening before finishing.  Some strands of archaeological evidence suggest that early medieval boat and ship builders in NW Europe were well aware of the issue of controlling seasoning. There is evidence of wet-stored rough out timbers such as the Eigg stem.  Very acid bog water or salt water would probably be best.

One of Damian’s sketches illustrating different log sections

Splitting before use may reduce drying distortion.  Radial cleaving, ie splitting the trunk across the diameter then again across the radius of each piece, produces the greatest natural strength in planks. A tangential split, ie splitting off a piece not directly across the diameter is less strong.  We believe that the Anglo-Saxons did not have saws of any size (unlike the Romans or later the Vikings) so splitting using one of these methods would have been used to produce planks.  The cleft plank would be finished (hewn) nicely with side axes.

A close look at the Bayeux embroidery shipbuilding scenes shows that the roughed out cleft boards were put up in the tree crotches to dry after splitting.  This suggests partial rapid drying of those thin hull boards.  This can only achieved without massive distortion and splitting using radially cleft boards (not tangentially cleft and hewn or sawn planks).  Oak that has been converted into boards the ancient way using radial cleaving shrinks much less (about 50%) because of the way the timber is structured.  Splitting and distortion is also limited.

Partial drying, when the wood is still relatively green, also has the advantage of making bending easier. Think of bending a fresh stick of celery compared with a slightly wilted one – the latter is much easier, but the celery is still green.  With the easy lines and gentle bends of the Sutton Hoo Ship this is only of academic interest – it probably wouldn’t have been an issue.”