Shipshape 9

How to Build an Anglo-Saxon ship

Paul Constantine

Progress – Planks and Ribs

Following the clinking of the first rivet in December 2022, 2023 was mainly a year of adding planks/strakes. It sounds easy to say, but each plank takes an extraordinary effort to rive, to shape, to offer up and attach. The overlapping areas along plank edges are called ‘Lands’ and they have to be shaped (Left) very carefully, so as to provide a watertight mating surface between the boards, when attached with caulking between them. The recipe for this is in Shipshape 6. The planks are not continuous lengths, so they need to be attached to each other with scarfs as described in Investigation 8 (Ship) & Shipshape 7. The backward angle of the scarf is arranged to ‘shed’ not ‘collect’ water.

Preparing Planks

To prepare the planks requires continuous work well ahead of the time when each plank section is to be added. The riven pieces have to be painstakingly refined to get their final smooth shape (Shipshape 7). This can be a long and tedious job requiring intense concentration at every stage. The hands and wrists of the team are not accustomed to the repetitive shock of the blows of the axes and there are periods when working time is limited. Repetitive strain is a real possibility. All around the Longshed planks were in different stages of being shaped.

Each planks section needs to have a pattern made for it and as the shaping nears completion the planks may need offering up several times for adjustment and fitting. This is not a job for only one or two people. It takes several people to hold the heavy plank section in place whilst high spots are identified for trimming.These are the patient heroes (Right) of the build. ‘They also serve who only stand and wait.’  After a few shavings have been removed the plank must be offered up again. This third plank is being offered up with two people working on it and three more holding it in position.

Ribs

Eventually, the planks will be supported by the internal ribs of the ship. The half-model has been most useful for gaining experience of this process. Each rib has to be shaped on its outside to fit the planking, so it can be imagined that this is a huge challenge. Making and fitting the majority of the ribs may be mainly a future task, but work has already been going ahead on them.

Ribs Types

Scandinavian. It is worth pulling together some informion on how the ribs can be made and have been made on other craft. Going back to about 300BC we have the Hjortspring ship (See Investigation 3c under Ship on this website) where the ribs/frames were made of Hazel bent to shape (Left) and tied with Lime bast to cleats hewn from the solid planks. At about 300 AD we have the Nydam ship (See Investigation 3b under Ship) which continued to use cleverly-shaped, solid-oak ribs tied to strong cleats (Right). This method of tying ribs is quintessentially a Scandinavian method. The Oseberg and Gokstad ships used this method in their lower planks 300 years later.

The Mediterranean method of using ribs during a similar timescale, was to build the form of the ship with the ribs first and then add the planking afterwards. These ribs were large, square and closely spaced. Their outward surface was smooth not stepped, for the planking was edge-jointed not overlapped. This is the Carvel style. Roman craft predominantly used this method. (Left) This is the Kyrenia ship dated roughly 300BC, so it is contemporary with the Hjortspring boat. It was found just off the north coast of Cyprus. It was a sailing, trading vessel. At 14m (47ft) long it was a similar length to our Sae Wylfing, but its beam at 4.4m (14.6ft) its weight and strength make it a totally different kind of craft. It was carrying a cargo of 380 amphora, almonds and even 30 millstones with other mixed goods, which would have not been possible on the lightweight Scandinavian craft of the time. True Roman craft from the Middle Rhine area show very similar construction methods. Look at the close spacing and dimensions of the ribs at the base of the photograph.

Hybrid

It is of interest to observe that our Anglo-Saxon ship is a hybrid of the two systems, which may not be surprising as the Romans had occupied Britain for 400 years prior to the beginning of the Anglo-Saxon migration. Naval Architect, Paul Handley (Investigations 4 & 8) scrutinised the dimensions of the ship and concluded, by comparing them in other measurement systems, that the Roman system had been used (See full explanation Shipshape 1). The ship was built planking first and then the ribs added afterwards. To ensure good support the outer surface of the rib has to be ‘joggled’ to meet the plank shape. This entails a great deal of pattern making and laborious shaping (See below). This is seen in the 'practice' half model (Shipshape 3). In the upper part of the picture a rough softwood frame has been used to obtain the correct planking shape.

To the lower right there is a rib section of the correct, rectangular dimensions. It is secured with two wedged trenails to the planking. Pieces of plywood have been shaped and attached to each other to discover the shape of the next adjoining section. They indicate the form of the outside face of the rib. Small holes have been left on the top side of the planks in the lower part of the boat. These are 'limber holes' that allow bilge water to pass the rib, so that it can drain into a central location to be bailed out. (Below) A rib section being trimmed to size for attachment.

Grown or Composite ribs?

The Nydam ship had ‘grown’ ribs, that is, naturally-shaped wood was selected from which to cut each rib. The grain flow makes them strong. The picture left, from Thomas Finderup, shows a pattern being compared to a tree. A smaller pattern held at arm's length can be compared to a growing tree from a distance, to judge whether it is likely to provide a match. In the Anglo-Saxon ship it is not known whether the ribs were 'grown' or ‘composite’. Finding timber of the correct shape for grown ribs is extremely difficult. This was probably the most difficult challenge facing the builders if they wished to pursue it. As there was no indication of the construction method, it made good sense to plan to use composite ribs where grown ribs were not available. It can be seen that narrow ‘V’ shaped ribs near to the ends of the ship could be shaped from the junction of a branch with the trunk, but the wider, curving shapes in the centre of the ship would have to be made by joining timbers together. It is also possible to combine the two systems. The picture right is of the Myklebust ship showing a grown rib and the left-hand arm has had an extension added at the top, probably because a natural split weakened that part of the rib.

Riving Large Logs

To rive a large log takes some strength. To provide the manpower, soldiers from the local barracks were invited to help the voluteers in driving the wedges. It was not an easy job and they had to take occasional rests, working in rotation. We can speculate that they are probably more representative of the young men who were involved in the construction of the original craft - but under the guidance of the wisest experienced men, of course!  When a log of this size is about to be split the two halves will roll apart and they are of a dangerous weight.. Wedges are used as chocks and rope bands are tied around them to control the sections as they fall. This was happening in June.

One-fifth model

This model is always ahead of the actual ship build and towards the end of the year its ribs were almost completely installed. Just like the ship, each rib had to have accurate patterns made. The smaller scale allowed an adjustable device to be made so that the position of each plank could be registered for transfer onto the appropriate rib.

 Bow and Stern

Approaching the end of 2023 the bow and stern planking was gradually creeping towards the centre of the ship. Two pictures of the bow show the beautiful grain pattern and the figure of the oak. The presence of internal frames means that some rivets have to be missed at this stage, to be inserted later. A temporary screw holds the end of the planking in shape prior to the insertion of the next section of the planking, when it can be replaced by a rivet.