Building an Irish Logboat

Goals

The goal of this project was to create a functional logboat appropriate to early medieval Ireland using period materials and tools (or functionally equivalent substitutes when necessary) and following a sequence of operations suggested by period examples.

Type & Shape

This logboat is a “simple logboat” which means it has been made of a single log which once carved out has not had it’s sides extended (raised by the addition of wash strakes) or expanded (had them softened by heat or soaking and spread apart).

For further explanation see: Expansion_and_extension_of_logboats_Terminology_base_for_Upper_Chickahominy_Logboat

The shape of this logboat is of the “canoe” type, one of six logboat hull forms found in Irish and Scottish logboats as described and defined by Gregory, 1997.

Dimensions

This logboat falls within the size range of known examples but is at the extreme short end of the length range.

Length: 2.14m (7′-3″) long. Range in period examples: 1.83m – 16.76m. Majority 3m – 8m.

Width: 53cm (21″ maximum) wide. Range in period examples: < 40cm – 1.44m. Majority 50cm – 1m.

Depth: 31cm (12″) deep. Range in period examples: 12cm – 1.04m. Majority 20cm – 39cm.

Bottom thickness: 5cm (2″) thick. Range in period examples: 3cm – 11cm.

Materials: The Log

Logboats by definition are made from a log. The recovered examples of logboats in Ireland are with several rare exceptions made from green logs of Irish oak (Quercus petra). Living in North America I do not have ready access to Irish oak. While there are many oak species native to this continent I live in a region where the only species capable of producing a log of sufficient size is northern red oak (Quercus rubra) which has properties that make it a poor material for boat building of any kind. (For a demonstration why see this video: https://m.youtube.com/watch?v=L6t2AZubF8U ) In the end I did not choose an alternative tree species for my logboat so much as it chose me.

Two friends were removing a large old sugar maple (Acer sacchaum) from their property and knowing I had been looking for a suitable log offered me one. It was 7’-3” long, the butt end was 25-1/2” across and the top end 19”. An estimate based on length, the diameters of each end, species and water content came in at 1,100 to 1,200 pounds.

The log in my back yard and ready for the work to begin.

Tools and Supplies:

Other than a chainsaw to trim the log prior to moving it to my home I used only hand tools. I limited myself to types of tools that were available in early medieval Ireland. For moving the log, especially in the early stages of the work: an iron pry bar, wooden poles and rope. For wood removal and shaping: axe, adze, gluts (wooden wedges), iron wedges, maul and mallet. For measuring and marking: string, awl, chalk and charcoal. For installing depth gauges: brace, spoon-bit, charcoal and knife.

There where several other tools which I tried out on the project but which proved to be of little practical use and I set aside: Scrub plane, large chisel, hatchet and draw-knife.

Sequence of work

In building this logboat I used an order of basic operations suggested by a number of Irish logboat finds. These finds are of unfinished logboats that were abandoned or lost at various stages of construction. Examination of these reveal that the builders shaped the exterior first and then the interior, used the trough and splitting method to remove much of the interior wood, and used depth gauges to control the thickness of the hull. Using my experience as a woodworker I broke that order of construction down further, into six steps: marking the centerline and gunnels, removing the wood above the gunnels, shaping the exterior, roughing out the interior, installing the depth gauges, and final shaping and trimming of the interior. All six of these steps together took a total of thirty hours of labor.

Step 1: Marking the center line and gunnel height.

Winding sticks being used to define the gunnel height.

Step 2: Removing the wood above the gunnel line using trough and splitting technique.

First trough cut and gluts started, all with an axe.

Step 3: Shaping the exterior.

The log rolled upside down and the bark peeled off.

Step 4: Roughing out the interior using trough and splitting.

The trough and splitting method is used to rough out the interior of the boat.

Step 5: Setting depth gauges.

The purpose of the depth gauges is to control the thickness of the hull. Holes are made in the finished exterior as deep as the builders want the hull to be thick. In this case, two inches. Wooden pegs are then driven into those holes. The pegs are usually made of wood that contrasts in color to the hull, or are stained or colored. In this case, they were stained black with ground charcoal. Then as the builders remove wood from the interior of the logboat, they will eventually cut into the ends of the depth gauge pegs, revealing them. Seeing the end of a peg tells the builders they have reached the desire hull thickness in that area.

Holes for the depth gauges have been drilled with a spoon-bit and the tools and materials are laid out for installing the gauges.

Step 6: Finishing up the interior with adze and axe.

Using the gutter adze to remove wood from the inside of the bow.

Removing wood from the interior of the sides with an axe.

Testing performance.

Testing the performance of the logboat was done on two occasions. The first was in a small duck pond which is shown in the two videos below. After this initial testing, when not in use the boat was submerged in this pond for storage until it was moved to winter storage.

Video courtesy of Lord Calvius Nero.

Lord Oleksander Brazhnyk Video courtesy of Lord Calvius Nero.

A second more lengthy test of the boat’s performance was conducted on Moosehorn Stream in Orland. Maine. On this outing I paddled a quarter mile down Moosehorn Stream to it’s confluence with Hot Hole Stream where I engaged in several activities and then returned the quarter mile upstream. The activities at the confluence included checking woven eel traps, moving a trap across the stream, exiting and re-entering the boat on a marshy bank, and maneuvering in the more complex currents at the confluence of the two streams. This test was part of a group video production documenting not only my logboat but also two coracles, woven eel traps, a handmade drift net, and four SCAadians in garb. The photo below is a still from that video. The video can be viewed here: https://www.youtube.com/watch?v=NS2SddH18pM

Giving the logboat and myself a workout.
Photo courtesy of Shu Pate.

As expected, the logboat’s performance was strongly constrained by the size of the log used.

Stability: The relatively small diameter of the log prevented altering the rounded exterior cross section without losing the interior volume and buoyancy needed to keep me afloat. This unsurprisingly has resulted in a very tippy boat. Paddling while kneeling is difficult and nerve-wracking. Lowering the center of mass by sitting on the bottom of the boat improves the stability noticeably.

Maneuverability: The log’s short length makes for a very agile boat. It is capable of pivoting in it’s own length with very little effort with the paddle.

Tracking: Good tracking is the ability of a boat to move forward on a straight course with little need for course correction by the paddler. While the boat’s short length makes for an agile craft, it also results in poor tracking. It requires careful attention and corrective adjustments to each paddle stroke to maintain a straight course.

Comfort: Both short length and narrow width create a cramped interior space for a tallish adult paddler like myself.

General comments: For a person of my size this logboat is functional but awkward and at times an uncomfortable craft to use. For a smaller adult or child it may be less so. Its small volume and poor tracking make it a poor choice for carrying loads, long distance travel or use on larger bodies of water. On the other hand, it’s small size and agility could be quite useful for short trips and activities on small ponds, marshes and slow streams.

Challenges encountered and lessons learned

Because the log I used was from an old tree, I encountered areas of spalting, discoloration caused by fungi. These areas of the log tended to be soft or even punky, and as the work took place over the course of several months, even sprouted the occasional shelf fungus. For future logboats I will take more time and effort sourcing a log from a healthy mature tree that has not yet begun to decline.

Irish logboats were made from green logs which made working the hard oak easier. While I used a green maple log, my work on the project was spread out over a number of months. This allowed the log to begin to dry out, a process that was accelerated as I removed wood, creating more surface area. Covering the boat between work sessions with wet blankets and a plastic tarp, or filling it with water when it was right side up, was partially successful in slowing the drying.

In spite of my efforts, the wood began to check. This was particularly noticeable in the bow and stern. The archaeological record indicates that this was not an uncommon problem in period logboats and some finds offer solutions used by the early medieval Irish boat builder. There is one known example of a logboat repaired with an iron patch nailed over damage to the hull. There are several other finds that suggest that sphagnum moss had been used to caulk or chink splits and cracks in the hull. I successfully used both techniques to repair and seal cracks in the hull of my logboat.

What next?

The construction of the boat having been completed and my original goals achieved, I turned my attention to the problem of winter storage. The consensus among logboat scholars is that Irish logboats were maintained and preserved by keeping them wet and that they were intentionally submerged for long-term storage. Needing a way to store my boat over the winter, I have turned my need into an experimental archeology project. My boat has been moved to a remote pond, tethered to the shore, filled with rocks and sunk where there are several feet of water above it. My hope is that it is deep enough to keep it below the thick winter ice, an issue that would not have been as much of a concern in the milder winter weather of Ireland. In the spring I will return and recover it, hopefully to find it sound and functional.

A view toward the hidden place I chose to sink the logboat.

Another logboat?

Well, yes! Now that I know I can build one that floats, I want to build one large enough that I can paddle it comfortably and carry some gear as well. I’ll be looking for a longer, wider log from a mature healthy tree. Next time I hope to recruit a team and build it over the course of a long weekend. Possibly at the Endewearde Hunt. I may build a different hull shape if the log allows: a punt or transom-sterned canoe.

Sources

Fry, Malcolm F. (2000) Coiti: Logboats from Northern Ireland, Northern Ireland Archaeological Monographs: No 4, Antrim (Greystone Press)

Gregory, N.T.N. (1997) A Comparative study of Irish and Scottish logboats [online]. Available at: https://era.ed.ac.uk/handle/1842/7517 (accessed 26 October 20222)

Gregory, N.T.N. (1998) ‘The Lurgan Dugout Boat: Work in Progress – Delays Expected’, Archaeology Ireland, vol.12 (No.2, Issue No.44 / Summer, 1998), pp 30-32. [online]. Available at: https://milltown.galwaycommunityheritage.org/content/townlands/the-lurgan-dugout-boat-2 (Accessed: 8 December 2022)

Holtzman, Bob (2019) Indigenous Boats: Why Oak? Material Choice in British and Irish Logboats, Blog Post:
http://indigenousboats.blogspot.com/2019/12/why-oak-material-choice-in-british-and.html

Sauzedde, Louis (2014) Wooden Boat Building with Louis Sauzedde: White Oak vs Red Oak (YouTube channe: Tips From the Shipwright. https://www.youtube.com/watch?app=desktop&v=L6t2AZubF8U

Acknowledgements and thanks

Lady Admiranda Howard & Lord Rufus Apicius Grippudd for the generous gift of the log that could have been firewood warming their home.

Syr Cedric of Thanet for the loan of his adzes and the woven eel trap that I got to play with while paddling my logboat.

Lord Oleksander Brazhnyk & Lady Anya Krasnoperkin for the use of their duck pond to test & store my logboat.

Lord William of Wyndhaven, Lord Gwillim Kynith, Lady Hrefna Hróbjartsdóttir & Shu Pate for a great day on Moosehorn Stream playing in garb in our boats with eel traps and nets. I’m looking forward to the video!

Lord Gwillim Kynith again, for the company and help putting the logboat to bed for the winter.

Lord Calvius Nero for recording videos of the first duck pond test and allowing me to use them.

Shu Pate for recording the day on Moosehorn Stream and sharing the video and the photograph of me paddling my logboat.

To the many friends who have taken an interest in this project and offered words of encouragement.

And last but not least to my wife, Sherrie, for the patience, proofreading, and love.

Now it’s time to put my feet up and dream of warm breezes and still water.