The Brendan Voyage (43 page)

In effect, the tests showed that traditional oak-bark leather was very strong even when wet; that this strength did not diminish; and—from earlier data available at the Research Association—that the comparatively open-fiber structure of oak-bark leather rendered it particularly suitable for “stuffing” with a waterproof grease or dressing. Croggon’s of Grampound eventually supplied 57 “butts,” oxhides trimmed of their upper shoulder and leg skin, for the boat. These butts were oiled with cod oil, rolled, and rough-dried.

2.
Dressing.
The dressing of the 57 butts with grease was undertaken by Joseph Clayton and Sons under the supervision of Harold Birkin, whose own laboratory had been testing samples of greased leather in conjunction with the B.L.M.R.A. The
Navigatio
stated that the monks used “fat for preparing hides to cover the boat” and “smeared all the joints of the hides on the outside with fat,” so only fats and greases which were known from early medieval times were tested—tallow, beeswax, fish oil, and wool grease, singly and in mixture. The correct dressing was vital to the durability of the leather hull. The problem was not merely to grease the leather well enough so that it kept out the water, but to grease it without damaging the quality of the leather. If too much soft grease was put into the leather fibers, the leather became too limp; too little grease, and the leather was not water-tight. After very many experiments, it was found that the most suitable dressing was raw wool grease. This wool grease was given through the generosity of W. & J. Whitehead (Laisterdyke) Ltd., Top makers and Worsted Spinners of Bradford; and was put into the leather by dipping the oxhides in a bath of wool grease at 50°C. for up to twelve hours and then leaving the hides stacked for weeks, with grease between the layers to ensure complete penetration of the grease into the leather. This produced a 30- to 37-percent uptake of grease. The monks might have achieved the same result much more slowly by hand, applying successive dressings of wool grease to damp oxhides, or by pouring on hot grease and rubbing it in by hand. The success of the collaboration between Joseph Clayton and the B.L.M.R.A. in producing
Brendan
’s hull leather can be judged from the comparison between the leather first supplied to
Brendan
(Column a) and the same leather after it had crossed the Atlantic (Column b). In sum, there was no major change in the composition or performance of the leather from the beginning to the end of the voyage.

3.
Thongs.
W. & J. Richardson of Derby provided the two miles of leather thong which were used to lash
Brendan
’s frame together, also the thongs employed on board in place of short lengths of rope. Initially five different types of thong were sent to the research laboratories for testing and their values were shown as follows:

Alum-dressed thong—a system known at least in Roman times—was selected as the most suitable, and the thongs were treated with a tallow and fish-oil dressing before they were sent to
Brendan.

4.
Thread.
Henry Campbell and Company of Belfast made the 23 miles of flax thread which stitched
Brendan’s
oxhides together, and also made up the improved flax ropes for her rigging with the help of Belfast Rope Works. At the suggestion of James Henshall, the director concerned, samples of Campbell’s flax thread were tested (in conjunction with
Brendan
oak-bark leather) by the Shoe and Allied Trades Research Association.
Table IV
shows how well the flax thread performed in these tests, growing stronger when wetted and stronger again when sandwiched in oak-bark leather. It can also be assumed that the thread became more rot-proof when the tan from the leather migrated into the thread and discouraged bacterial decomposition.

The scantlings in Colin Mudie’s design for
Brendan
were of the order of 1″×6″ oak for the gunwales, 2″×⅝″ ash for frames, 2½″×⅝″ ash for stringers. The fore-and mainmasts, 12 and 19 feet long respectively, were initially cut as single ash saplings, but these developed splits during trials, and were replaced by single lengths cut from close-grained ash under the personal supervision of Paddy Glennon of Glennon Brothers, County Longford, who also provided all ash used for frames, stringers, and oars. The masts were set in socketed mast-steps of oak which rested directly on the keelson.

Pat Lake and Michael Murphy of Crosshaven Boatyard faired up the hull frame, which was then fastened with alum thong lashings. Each thong was pre-stretched by hand to reduce its initial elasticity,
soaked, and then hand-lashed in place while still wet. The fastened hull frame was then liberally coated with wool grease to preserve the timber. Subsequent inspection showed that the wool grease had penetrated deeply into the wood grain.

Forty-nine oxhide butts were needed to cover the boat. The hides averaged about one-quarter inch in thickness, and measured on average 45″ × 47″.

The thread to stitch the hides was “fourteen cord,” i.e., handrolled from 14 single threads. It was then waxed with a combination of wool grease, beeswax, and resin so that it filled the awl holes when drawn through. John o’Connell, harnessmaker, and Eddie Hinton, master saddler from the Walsall saddlery firm of Eldonian Brookes, decided the most suitable method of stitching. This was back-stitch for the hides along the center line of the boat, and double-handed stitching for the remainder of the work. The double-handed stitching had to be done by pairs of stitchers stationed opposite one another on each side of the leather. Stitch length was approximately two to the inch, and double lines of stitches were put in, approximately 1 inch apart. Every joint was a plain overlap of about 2 inches width. At the prow and the leading ridge of the keel, where collision and grounding were anticipated, John o’Connell overlapped four thicknesses of hide for extra strength. And at the stern an extra fillet of leather was applied at the keel to protect against stern beaching.

The keel-skid of oak was fastened through the leather with ½″ copper rivets. Riveting was a very highly developed technique in early Christian Ireland. The leather skin was not otherwise fastened directly to the hull frame but tensioned over it, pulled over the upper gunwale, and lashed down to the lower gunwale with hair-on round leather belting. Harold Birkin suggested this unusual use for hair-on belting, which was supplied by the Lion Leather Company.

1.
Rowing.
Five weeks after landfall at Musgrave Harbor,
Brendan
was in a very different setting to the wild Newfoundland coast. In sight of the skyscrapers of Boston on the lower Charles River she was rowed by ten volunteer oarsmen from the Union Boat Club. The purpose of the experiment was to try to find out just how many oarsmen, albeit inexperienced
in rowing leather boats, were needed to row
Brendan
effectively under different states.
Table V
illustrates what we had also learned from the voyage itself: namely that
Brendan
was severely undermanned with a crew of only four. But it also shows that a crew of ten oarsmen could make headway in all but very adverse conditions; and that under more favorable conditions a rowing crew of six or eight men could edge a cruising curragh upwind. It should be stressed, however, that the tests, our own ocean experience, and the medieval texts indicate that long-distance voyages in Irish leather boats would have been made under sail. oars would normally have been used in emergencies, when coasting, or when in sight of a landfall.

R
OWING
T
ESTS

Average of up- and downstream runs over 510-meter course, lower Charles River, in westerly wind Force 3 with a current of c. 1.3 knots.

N
OTE
: A coasting load was calculated as the stores and equipment needed for a curragh making day passages within sight of land. A full ocean load was calculated as the weight on board of water, food, and gear needed for a 3-week ocean passage for 10 men.

2.
Sail.
The lack of suitable instruments made it difficult to measure accurately
Brendan
’s performance under sail. obviously it was impractical to fit a “through hull” log impellor in an oxhide, and the only
feasible instrument was a trailing log. A Walker Knotmaster was used, and the manufacturers warned that their instrument was ineffective at speeds below two knots. However, on a cruising basis, the following observations were made:

a. The maximum distance achieved in a 24-hour period was 115 miles. The minimum day’s run was, of course, nil in a flat calm, and on bad days
Brendan
was actually set back on her course by adverse winds. The average day’s run under sail was 40 miles, and a cruising speed of 2 to 3 knots was considered satisfactory. This required a wind F 3–4 where the boat was fully laden. In ideal conditions of a following wind of F 5–6 the log would register sustained periods of 5 to 7 knots. The maximum reading on the log scale was 12 knots and this speed was achieved comparatively frequently in heavy weather and high seas, though in Mykines Sound in the Faroes a prolonged burst of 12+ knots was achieved due to the funneling effect of the surrounding cliffs.