February 2023 - The Sutton Hoo Ship's Company

We are now well into the phase of making, fitting and fixing the planking to the Ship. This involves taking a triangular cleaved section of oak log, turning it on its side to create notches along its length (imagine a Toblerone bar) and then removing the excess material between each notch with an axe. The remaining timber is then converted to a 1”/25mm plank (see my January Update for more details). The plank is then cut to the required profile so that it fits the line of the plank below it on the ship or to the rebate of the backbone for the garboard (lowest) strake. Before the plank is drilled and ready for the nails, caulking is applied, and the plank is fastened to the existing hull. Our caulking is a combination of pine tar, beeswax and animal fat slathered onto a strip of woollen fabric that sits snuggly between the planks to fill any gaps that the axed surfaced might leave.

Here is a section of the starboard No. 2 strake being offered up to its final location next to the starboard garboard strake of the ship.

In modern boatbuilding, the overlapping mating surfaces of a plank, known as ‘the lands’ would not be caulked. The smooth and accurate nature of modern planed timber means that once the vessel is in the water and has ‘taken up’ (reabsorbed water) there is a tight enough bond to ensure a watertight seal between the planking.

However, from the 4^th century Nydam Oak Boat (Southern Denmark, excavated 1860’s) we know that these early clinker-built vessels were caulked. Nydam showed evidence of a high-quality twill-weave woollen cloth set in a mix of birch tar, bees wax and animal fat (probably tallow which is a rendered sheep’s fat) placed between the overlapping areas of the planks and also the scarfs joining each section of planking together. Later, the Vikings appear to have used a similar, but different, method of cutting a semi-circular groove in the mating areas of the planking and fitting a spun skein of sheep wool set in a coating of pine tar – equivalent to a modern grommet. Following research early in the project we tested both of these methods when we started planking the full-scale midship section of the Ship in 2020. Both methods worked effectively, but since the earlier cloth method was known to have been used earlier than the time of Sutton Hoo, this was the method we chose to use.

Here you can see two sections of planking with the woollen cloth caulking fitted in between.

Here Jo Wood and David Turner are testing out the later Viking method of caulking by adding a skein of wool to a pre-made groove.

Our aim is to fit and fasten up at least two planks each week. If we meet this target then the Ship will be planked by the end of 2023, leaving 2024 for the fitting out of the Ship and making of oars and allowing for a Spring 2025 launch and sea trials.

One of the issues we are encountering is having timber that is wide enough and long enough to make the larger plank widths. The current log we are working with is 30”/760mm in diameter, but to get the required width of planking in the lower planks and at the end of the ship, we would have to cut the length of the planks too short to be viable. From the archaeology, the maximum lengths of planking are believed to have been around 18 feet/5.5m long. We have other logs of significantly greater diameter, but these are shorter in length and will be needed for the wider planking in the centre of the Ship. Another issue is having enough space to work in as any recent visitors will see that as the ship starts to grow we are having to work in very cramped conditions. These modern-day issues were unlikely to have been a problem to our Anglo-Saxon ancestors who would have had unlimited space and plenty of larger timber.

Next month will hopefully relieve some of these issues as we will cleave the next log – which is of a greater diameter – as an outdoor public display over at the Sutton Hoo Estate. We are also exploring the possibility of working in the public area outside of the Longshed.

These are the two logs from the Blickling Hall Estate that will be cleaved at Sutton Hoo.

This is a planked section of the ship. In the centre you can see the top of the trenails that fasten the keel to the forward underloute. This is surrounded by rows of rivets that are joining the garboard and second plank to the hull.

We are using an alphanumeric code which unique to each plank and allows us to identify the origin of the plank for future research purposes.

The pale streaks of grain in the timber are called medullary rays and are indicative of radially cleaved timber (in modern techniques, ‘quarter-sawn’)

The 1:5 scale model continues to progress, with more frames being made and fitted temporarily. The model is a work of art and gives a real sense of how majestic the full ship will be.

We are experiencing a sharp rise in the number of talks and tours that we are giving. We love talking about our project and are ever grateful to the 90 volunteers that are building, guiding, recording, researching and administering for us – Thank You

Tim Kirk, Master Shipwright