Re: The design of the Swallow.


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Posted by John Nichols on March 08, 2003 at 18:36:34 from 165.91.199.202 user Mcneacail.

In Reply to: Re: The design of the Swallow. posted by Andrew Craig-Bennett on March 08, 2003 at 17:09:20:

Dear Ed and Andrew,

Thanks for the jpg file of the Scarab (Ed) and to Andrew for the comment on the timber.

I found this and will share it.
Ulmus Glabra - Wych Elm, Scots Elm. Irish
Leamhan.
Description
Large deciduous tree. Susceptible to Dutch Elm
disease and accordingly not planted any more.
Height 40m. Age up to 500 years
Habitat
Typical hedgerow tree but found up to 300m.
Requires non calcerous top soil. In mixed woods
with Whitebeam and small leave lime and in Oak
and Ash woods.
Natural Distribution
Common in North and West of Britain and Ireland. Native throughout Europe and W. Asia.
The Tree Year
Flowers Leaves Fruit Ripen Fall
Feb/March April/May May/June
Propagation and Growth
Grown from seed which is not dormant. Approx
40,000 seed per kg. Does not sucker. Takes
approx 30 years before seeds are produced and
then every 2 or 3 years. In the wild seed
germinate shortly after falling.
Timber
Strong and supple pale brown wood. Prone to
shake. Cannot be split leading to particular uses.
Does not decay when immersed in water.
Uses of Wood
Used to be used to make chests, water pipes and troughs and for sea defenses. Also for sections for cow sheds, cribs and mangers, hubs of wheels, coffins and furniture.
Food and Drink
Leaves once used for livestock.
Related Species
Various non - native species were common in
England but decimated by Dutch Elm Disease


I live in Texas so I am will need to look harder as to the timber I can get.

I put the Scarab plan (PM) into Autocad and then calibrated her to 14 feet. She has a height of 30 inches and a depth at the midships of 21 inches and is identical in those respects to the dimensions I had. The longitudal section fitted in all respects (although AR ) does not give quite as sweeping a sheer line. I went back and stared at his sketches of the boats and decided the one or so inch is irrelevant and I prefer the sketches to Dicks plan.

Scarabs transom was 40 inches, but her beam was 67 to 68 inches and I had only 64 inches. The measurements I made of Swallow suggest that AR drew her between 65ish and 68 inches. I looked in the wooden boat books and a working boat of 14 feet was probably 65ish inches at that time, a pleasure boat 62 to 65 inches.

Scarabs plan also shows a longish flattish section on the planking at the sheer line and the other views show a more fullsome curve.

So I am caught as this is a bit of a ticklish decision as it affects the width of the boat at the mast.

Scarabs mast is further forward than Swallows, and Roger would not be eating chocolate all year to get into that space.

Finally I put the Scarabs hull into the hull design program. The width at the beam and mast shown take about 10 per cent off her hull speed. I have just walked up and down five flights of stairs thinking about the implications and what would an academic father of two and an old boat builder have agreed to build, and did Dick sketch accurately.

And what number of bulkheads would the boat builder have used and where would he-she put them. The timber has to follow a smooth buildable curve, differentialbe at least once so to speak.

I need to think on this point although I am inclined to the thoughts of Gardner who was building wooden boats at this time and who showed what knowledge these old guys had and she should have a width of not more than 65 inches and be a bit finer in the bows.

Gardner also tells of using WRC for the hull but notes that the boat needs to be treated well and not used for lobstering.

This old grey haired sailor is gunna think hard on this problem, any comments appreciated.

Also I have no idea how they attached the boom to the mast. Would anyone know how the gaff is attached to the mast. What sort of blocks would they have used and any ideas on the main sheet arrangement.

Interestingly enough the Scarab shows that the halyard is used as a forward stay, which is covered in one or two of the common designs for that period.

AR knew his sailing stuff, but I am still thinking on the width of the boat at the mast.

He also seemed to like the fully enlcosed seating area for the Captain which is a feature of the Amazon but not the Swallow.

Anyway I gotta go write proposals.

John






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