Timber for skin on frame rowboat

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Forthsailoar Forthsailoar
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Timber for skin on frame rowboat

Hi

I'm thinking of building a SOF rowing boat. I've been discussing designs over at the wooden boat forum, and am tending towards the LFH17 - using Mikalak plans (see duckworks for article on a sof version) (sorry for lack of links, writing this on my phone, too fiddley).

My main question is a suitable timber for the stringers. I'd like to make this a fairly low cost effort, and wonder if I could use stuff available from a mainstream timber merchant. I'll need 18' lengths which will probably mean scarfing, which is fine. I'd like to use stock sizes - or stock sizes ripped to equal widths. I have no power saws.

When I look a timber merchant sites all I see are 'white' or 'red' timber! The latter sometimes described as Scandinavian pine, claiming to be slow grown 80 years plus, with straight grain. Is the red likely to be suitable?

Thanks!

Jeremy Jeremy
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Re: Timber for skin on frame rowboat

momist momist
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Re: Timber for skin on frame rowboat

In reply to this post by Forthsailoar
Red, or reds, is usually much better quality than the white, but both are low quality compared to any 'hardwood'.  Hardwood, confusingly, does not relate to the hardness of the timber.  The red is usually quite a lot heavier and harder than the white, but also stronger.  

The problems you will encounter are:
1.  Durability.  Both will absorb moisture readily, and rot will set in if left wet.
2.  Knots.  Both can be very knotty, and the only way to get suitable timber for what you want will be to go to a timber merchant who lets you select for yourself.  Luckily, I have a choice of such merchants here, but you may not.
3.  Strength of joints.  Softwood needs more robust joints, which equates to larger sections and therefore larger timber to begin with.

The answer to all these problems lies with epoxy resin which adheres very well to softwoods and actually strengthens the wood.  Epoxy will let you cut out knots and scarf the remains to give long clear lengths, although this can be a very laborious process.

Softwood also needs sharper tools (confusingly!) as the fibers are more prone to fraying out and leaving a poor finish.

If you are going for something different, look for an alternative structure.  How about plastic pipe?  That latest version of water pipe for plumbing looks interesting.
Forthsailoar Forthsailoar
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Re: Timber for skin on frame rowboat

Hi Momist

Thanks, very helpful. As I feared regarding knots etc. I did buy some western red cedar from Robbins for my Walkabout, lovely but expensive. I'm trying to avoid the hassle of epoxy, so I'll need to look seriously at the alternatives, aluminium etc. What's the water pipe you mention? (Though I'd rather avoid the embedded energy of alu and plastic...)

I'll also try and find a real sawmill reasonably locally and pick the brains of a friend who works in forestry and always seems to know some one who get stuff...

Cheers

Osbert
~
forthsailoar.osbert.org
Timmo Timmo
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Re: Timber for skin on frame rowboat

You're getting good advice so I'll add just two comments, both assuming you stick with wood rather than going the aluminium or plasic route: 

Robbins are good but generally expensive for timber. Alternative sources are harder to find but often much cheaper.

You could be goining to a lot of trouble and expense that might be saved if you did invest in a small table saw. Doesn't have to be fancy or expensive to rip boards to your spec and the flexibility having your own saw offers you is well worth the investment. Can be used to cut scarphs very quickly and accurately too. If you've space to store and use one the cost (especialy of a used one) could be covered in savings on just one boat.

Tim.


On 4 Jan 2014, at 15:30, Forthsailoar [via UK HBBR Forum] <[hidden email]> wrote:

Hi Momist

Thanks, very helpful. As I feared regarding knots etc. I did buy some western red cedar from Robbins for my Walkabout, lovely but expensive. I'm trying to avoid the hassle of epoxy, so I'll need to look seriously at the alternatives, aluminium etc. What's the water pipe you mention? (Though I'd rather avoid the embedded energy of alu and plastic...)

I'll also try and find a real sawmill reasonably locally and pick the brains of a friend who works in forestry and always seems to know some one who get stuff...

Cheers

Osbert
~
forthsailoar.osbert.org


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momist momist
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Re: Timber for skin on frame rowboat

In reply to this post by Forthsailoar
Osbert, The pipe I referred to was PE-X.  Cross linked polyethylene.  Details from Screwfix:

Cross linked Polyethylene (PE-X) Plastic Pipe to BS 7291. Use with Speedfit pipe inserts. Push straight onto copper tube. Removable and reusable. Water Research Council Approved. British Gas Service approved for water pipes. No tools needed. BS 7291 / PT1 / PT3. Kitemarked.

I've bought one length (2m) to play with and it seems both very strong, light and durable.  Plumbers now (allegedly) use this in preference to copper because it will take an open radius curve without needing bending equipment, seals to either copper or push-fit connectors (only the ones designed for it!) and makes the whole job quicker.  Whether I would trust it to re-plumb my whole house, I'm not yet sure, but with a bit of the right glue and fittings it would make a structural and resilient shape, with curves, quite easily.  I came across it from a USA reference where someone used it both for holes through and for the handles on his dinghy.

Red Cedar is a lovely wood to use, though soft.  Nothing to do with redwood.

Good luck with your project.
Ian
Jeremy Jeremy
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Re: Timber for skin on frame rowboat

I've just plumbed my new house with PEX.  Half a day to put in all the first fix hot and cold water pipes, dead easy to use and no joints hidden under floors or in walls.

Not very stiff though, and I doubt that it would be useful structurally, especially as nothing seems to stick to it, as it seems un-glueable.
simplesimon simplesimon
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Re: Timber for skin on frame rowboat

In reply to this post by Timmo
Ash, if you can get it - but will need protecting

Simon
Whameller Whameller
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Re: Timber for skin on frame rowboat

Osbert,

I used Southern Yellow Pine from a local timber merchant for the stringers of a 14' Tom Yost SOF kayak.  Worked very well - came in long enough knot-free lengths not to require scarphing.  I used standard sizes, having worked out which of these bought PAR would be closest to what I wanted.

Epoxy coated, they have now seen 2 seasons of hard use by a teenage son with no issues at all.

Nick W