Advice saught for strip planking wood

[Doug Teggin]

I am building a 15 foot sail-and-oar boat, strip planked. Strips are 22mm wide and 15mm thick (hull thickness).

The architect advises: Douglas Fir, Red Pine, Spruce, Mahogany or Sipo for an unsheathed hull (no fiberglass cloth). The resin woods here average about 510kg/m³. The mahoganies are 600 to 650 kg/m³ on average.
I don't have any of those woods nearby, and would have to order from afar and unseen.

I have a local sawmill that produces Oak (700 kg/m³), Ash (680 kg/m³), Poplar (450 kg/m³), European Beech (710 kg/m³), Tilia (535 kg/m³), Sycamore (615 kg/m³), Wild Cherry (600 kg/m³) and Hornbeam (735 kg/m³).

Hornbeam has irregular grain and is hard to work. Oak of course was used in traditional planking for centuries, but can any of these others be used on a strip planked hull, glued with epoxy?

[WI-Tom]

Hornbeam and oak are pretty heavy for a small boat. I've never heard of either of them used in strip planking, but that may be because of the weight. It may also be because pine and cedar were common where traditional strip-planked construction was used. The big advantage was not needing wide planking stock.

I'll be interested to hear what the knowledgeable people have to say. I'm leaning toward "no way, use pine or something similar"--but I'm no expert. The fact that you won't be able to pick through the wood is a complication for sure.

That said, the big-box home improvement stores around the U.S. Midwest carry radiata pine from New Zealand. If you buy the select grade nominal 1x lumber, it's absolutely free of knots. That's what I used in my boat. Back then it was fairly cheap--less than $400 to plank an 18-footer, with 1" x 1/2" strips. I might buy this kind of select-grade radiata sight unseen if I had to.

Tom

[johngsandusky]

I think the problem with oak will be it's shrinking and swelling. Maybe cherry?

[dutchpp]

For an unsheathed boat that's a difficult question:
Hornbeam and oak are indeed too heavy, however you could reduce the thickness the oak strips with 1 mm that would give you a strip of approximately the same weight and probably approximately the same strength as a mahogany strip (I've used 5,1 meter*0,022*0,015m for the calculation, oak is strong)
Ash, Poplar and European beech are prone to rot and discoloration.
Tillia is probably too soft for unsheathed use.
Sycamore, strength is ok but I'm not sure about it's unsheathed durability, looks nice though!
So in this specific case my choice would be Cherry ( reasonably strong and durable), or with a modified strip thickness Oak although it may be hard to glue properly with epoxy and has some tendency to swell a bit more if its unsheathed, so my first choice would probably be the Cherry

If you set the strips in epoxy and glass you can use some other woods as well. Some guys in the Netherlands used the low weight Poplar wood sheathed in epoxy and glass for a high speed runabout with good results.

[WI-Tom]

If you set the strips in epoxy and glass you can use some other woods as well. Some guys in the Netherlands used the low weight Poplar wood sheathed in epoxy and glass for a high speed runabout with good results.

Relying on glass (both sides) for the structural strength is an entirely different form of construction than strip planking with heftier unsheathed planks. Not saying it can't be done that way, but it would change everything about the construction details, I think. Certainly the strips as designed would be far thicker than necessary if you went this route.

I suppose you could sheath both sides strictly as a rot preventative measure, without changing construction details, but that kind of removes the advantage of not needing to glass a traditional strip-planked hull.

Tom

[Andrew Donald]

Hornbeam and oak are pretty heavy for a small boat. I've never heard of either of them used in strip planking, but that may be because of the weight. It may also be because pine and cedar were common where traditional strip-planked construction was used. The big advantage was not needing wide planking stock.

I'll be interested to hear what the knowledgeable people have to say. I'm leaning toward "no way, use pine or something similar"--but I'm no expert. The fact that you won't be able to pick through the wood is a complication for sure.

That said, the big-box home improvement stores around the U.S. Midwest carry radiata pine from New Zealand. If you buy the select grade nominal 1x lumber, it's absolutely free of knots. That's what I used in my boat. Back then it was fairly cheap--less than $400 to plank an 18-footer, with 1" x 1/2" strips. I might buy this kind of select-grade radiata sight unseen if I had to.

Tom

DO NOT use radiate pine. It rots before you get the fibreglass on it. I’m from from Australia and it’s everywhere here but not in boats

[Peerie Maa]

With that list of timber, I wonder whether is larch available?

[Thad]

From that list I'd think tilia or poplar. As with any wood, use air dry and stick with heartwood.

[WI-Tom]

DO NOT use radiate pine. It rots before you get the fibreglass on it. I’m from from Australia and it’s everywhere here but not in boats

Yep, I figured this kind of comment would show up soon.

This boat:

DSCN3310 cropped.jpg

is planked with radiata pine. 1" x 1/2" strips, edge-nailed and glued. No glass necessary, though I did glass the outside for abrasion resistance and maybe extra waterproofing. After 5 years and over 1,000 miles so far, there's no sign of rot.

Keep it painted, store it indoors or under cover, keep it dry, and it shouldn't be a problem. It actually compares quite favorably to other softwoods as far as strength and weight, I think. I looked all that up once.

Tom

[Andrew Donald]

Sounds like you look after it pretty good Tom, you’ve found the secret of looking after any boat. Still wouldn’t be on my list. Most Australians/Kiwis prob wouldn’t have it either.

id be going with DF before it but even that can rot sooner or later. I’ve replaced enough barge boards on houses to turn me off it unless we’ll protected and under cover. My boat is framed with it (tight grained DF that is) - Inside and epoxy coated.

can’t imagine everyone will look after their boat as good as you. Sure it’s light, and a bit stronger than cedar. Works very well , nails glues and screws well too.

All of it outside here is pressure treated.

Forewarned is Forearmed Doug, just sayin. If you must use it - look after it and glass the outside at least, it’s pretty soft (slightly harder than WRC)

one other thing, if you went from 500kg/m3 to say 650kg/m3 that’s for a whole cubic metre you won’t be using anywhere near that much so your weight difference maybe 10-20 kg. Not a lot. Momentum.

[Woxbox]

Of that list, I'd go with Poplar and seal it up good. I assume it will spend most of its time out of the weather?

[wizbang 13]

Where are you Doug?
AYC is the best for this, imo.

[Hugh MacD]

I assume you got your data from the Wood Database, but just in case: https://www.wood-database.com/ I've not done a strip plank, so I have no advice there. Tillia I thought was Basswood. Great for carving, but I'd really question its strength.

[JimConlin]

Tell us more about the boat design.
Length, beam, depth, sail area
Will the hull have internal framing?
Will it have structural sheathing, inside and out? I.e., is it strip planked or strip composite?
What’s your target weight?

[P.I. Stazzer-Newt]

Where are you Doug?
AYC is the best for this, imo.

The Where question is critical.

The species list and units suggest either UK or northern Europe be aware that sycamore and poplar are very different timbers each side of the Atlantic.

The AYC suggestion ( Alaskan yellow cedar) is a good call but it's not that easy to find in the UK.

[Edward Pearson]

Stones Boatyard import the best close grained quarter sawn AYC planks to the UK. As well as Sitka Spruce. I bought a boat full straight grained vertical grain 25 ringd per inch or so, and its perfect timber. As said earlier, the best timber for a stripper of quality would be AYC. Its the most durable timber that glues well. I’d use Sapeli for outer keel, stem, gunwales etc for the trailer dings. Tough interlocked grain doesnt split, finishes better than mahogany when varnished. Easy to get in the uk. If you’re in UK? Theres a company selling strip planks in the uk to order, they do the donkey work cutting etc. Supply what you want. Advertise in back of watercraft. It'll cost more but avoids the work of putting through a saw and there is alot of waste. Cost more but convenient and delivered.

https://cedar-strip.co.uk/about_strip_planking.html

There's also Fyne Boat Kits in Cumbria that will sell you Cedar Strip by the meter if you're north of England.

If you want cheap, i’d go down to a builders yard and look at the high spec softwood roofing timber joists etc. They are graded so you know they are almost knot free etc. Get alot of strips out of one. You can use baltic redwood similar to pine that you find everywhere for houses in b&q etc. If you want free, you can saw the sides off doors fown your local tip and get some good wood!

If you sift carefully, on ebay there are quite a few old joists pulled out of demolition sites that are old growth american pitch pine beams. Very close grain and durable. If you can avoid ones with nail holes etc, you can get some very good wood after resawing. Reclamation yards sell em. They’ll be 100-200 year old but still some of the best wood there ever was. Working on your own, you're going to have to organise infeed and outfeed tables from your saw. Thin kerf blades are available to reduce waste.

If you're not glassing but inserting cross dowels, it's probably going to be best to aim for lighter but thicker planking stock. Heavier species a mm or two less to compensate will give you less thickness to drive a cross dowel when it comes to that. Although not a native, woods of WRC and Sitka Spruce species were planted in England after the war and do get harvested and show up. Won't be as close grained as the imported stuff, unless maybe you find some in the North of Scotland.

There were some very big baulks of close grained Siberian Larch available, sold as sleepers that I thought would be a good source of decent timber (I was looking for a workbench). Quite long 10-12ft too, so you just need a scarf, but cheap. You'd have to pick it up as delivery would be alot. I'm guessing they're not coming in from Russia anymore. You'd need a manly bandsaw.

[Wayne Poulsen]

[QUOTE=Andrew Donald;6687042]DO NOT use radiate pine. It rots before you get the fibreglass on it. I’m from from Australia and it’s everywhere here but not in boats[/
radiata is a weed .
zero durability.
OK (?) in a house if treated and kept dry
No place in a boat.

[Matt young]

Is the Poplar at your local mill air-dried?

[WI-Tom]

radiata is a weed .
zero durability.
OK (?) in a house if treated and kept dry
No place in a boat.

As Dr. Johnson might say, "I refute it thus!"

cropped photo B.jpg

Strip-planked in radiata pine. <$400 cost. 5 years and counting. Well over 1,000 miles of sailing and camp cruising without a problem, including:

S. Benjamin.jpg

And:

7.jpg

A dry-sailed trailer boat kept protected probably fails to justify quite the level of anti-radiata hostility showing up here, mostly (I'd guess) from people who have not (and would not) use it themselves. My boat still floats pretty well.

For comparison, virtually no one questions the use of occume, yet it is rated "non-durable" for rot resistance, just as radiata is.

But of course, there are plenty of other choices if the "non-durable" rating scares you. Just don't use occume!

Tom

[Andrew Donald]

As Dr. Johnson might say, "I refute it thus!"

cropped photo B.jpg

Strip-planked in radiata pine. <$400 cost. 5 years and counting. Well over 1,000 miles of sailing and camp cruising without a problem, including:

S. Benjamin.jpg

And:

7.jpg

A dry-sailed trailer boat kept protected probably fails to justify quite the level of anti-radiata hostility showing up here, mostly (I'd guess) from people who have not (and would not) use it themselves. My boat still floats pretty well.

For comparison, virtually no one questions the use of occume, yet it is rated "non-durable" for rot resistance, just as radiata is.

But of course, there are plenty of other choices if the "non-durable" rating scares you. Just don't use occume!

Tom

you’ve given a laugh for the day Tom. Guess what I’ve planked my lapstrake ply with?? Fair point. I am hoping the glue lines and epoxy coating may help to preserve it. I must say there’s very little choice here in Aus for durable species ply .

i must say that’s a nice looking boat you’ve built even if it’s Radiata!!

[NickW]

Theres a company selling strip planks in the uk to order, they do the donkey work cutting etc. Supply what you want. Advertise in back of watercraft. It'll cost more but avoids the work of putting through a saw and there is alot of waste. Cost more but convenient and delivered.

https://cedar-strip.co.uk/about_strip_planking.html

There's also Fyne Boat Kits in Cumbria that will sell you Cedar Strip by the meter if you're north of England.

If you want cheap, i’d go down to a builders yard and look at the high spec softwood roofing timber joists etc. They are graded so you know they are almost knot free etc. Get alot of strips out of one. You can use baltic redwood similar to pine that you find everywhere for houses in b&q etc. If you want free, you can saw the sides off doors fown your local tip and get some good wood!

.

Fyne Boats also supply Paulownia strips, cheaper (~20%), lighter (~20%) and more sustainable( grown in Spain approx 7 to 15 years from planting to harvest) than cedar. At present Fyne Boats are selling about 2/3 rds Paulownia to 1/3 rd cedar. See the article "Flat Packed Fleet" in Watercraft issue 153 May/June 2022.

Nick

https://www.fyneboatkits.co.uk/suppl...lownia-strips/

[WI-Tom]

you’ve given a laugh for the day Tom. Guess what I’ve planked my lapstrake ply with?? Fair point. I am hoping the glue lines and epoxy coating may help to preserve it. I must say there’s very little choice here in Aus for durable species ply .

i must say that’s a nice looking boat you’ve built even if it’s Radiata!!

Well, I also totally understand that radiata is not any kind of premium or "best" boatbuilding wood, for sure. For a traditional carvel or lapstrake build, no way. Or for a boat that has to live on a mooring. And you're right about glue lines protecting occume plywood, so not really a completely fair comparison.

My own sailing tends to happen on week-long+ trips a few times per summer. For at least 10 months of the year, my boat lives on its trailer out of the water. And I glassed the outside of the hull to try and protect it a bit more yet. That has to reduce the risk or rot significantly. As always, caveat emptor!

Tom

[WI-Tom]

Fyne Boats also supply Paulownia strips, cheaper (~20%), lighter (~20%) and more sustainable( grown in Spain approx 7 to 15 years from planting to harvest) than cedar. At present Fyne Boats are selling about 2/3 rds Paulownia to 1/3 rd cedar. See the article "Flat Packed Fleet" in Watercraft issue 153 May/June 2022.

Nick

https://www.fyneboatkits.co.uk/suppl...lownia-strips/

There's something to be said for ordering ready-made strips, especially if (like me) you have a home shop and no planer.

That was another reason I made my 1" x 1/2" strips from nominal 1x lumber--all it took was 2 passes through my tablesaw. The first pass made each board into 1" x 3/4" strips. The second pass made 1" x 1/2" strips. Yes, there was more waste involved that way, but I got acceptably uniform strips because I only had to move the set-up once, and all strips were cut with the same set-up. I think I cut all my strips (enough for 66 full-length strips on the hull, with extras for breakage, etc.) in one morning. Worked pretty well.

Tom

[wizbang 13]

No doubt, a big advantage of strip planking is that it does not require the worlds best wood .
but oak.....just no.

[Doug Teggin]

Thanks for the advice on these hardwoods. I'm in Northern France. The boat BTW is a strip planked Ilur (François Vivier design). I'm opting for strip planking now as the price of Marine Plywood is ridiculous, and there is a high percentage of waste after cutting out the boards from the plywood sheets. I just don't like that idea too much. Those hardwoods grow around here, hence the local sawmill works with them.

What I think I will do is order in some Douglas Fir, it is exotic to where I live, but it is grown in France. My issue with the Douglas Fir is the lack of choice of plank stock, "it comes as it is", says the dealer. I asked for quartersawn, but I think as the planks are 75 x 225 x 5000 mm I assume these are logs sliced up and not quarter-sawn. I'll have to do some milling. I can get Oregon Pine too from the same dealer. This hull will be painted so I'm not thinking Oregon is worth it as it is imported from Canada and thus expensive.

[JimConlin]

Douglas fir and Oregon pine are the same species, Pseudotsuga menzesii

[wizbang 13]

There is no advantage to paying for quartersawn for strip planking.
Consider making the planks square ,15 x 15 in your case , rather than 15 x 23.
This allows you go straight from the saw to the boat.Talk about zero waste!
And to lay the strip on in any grain direction you seek.
And being square simplifies scarphing , and re using (rescarphing) any planks that may break.
Grain run out is far more important than how the sawyer laid out the cut.
If planks "explode " when putting them on, it's because of poor grain run out, not because of air dried, or "verticle grain",or even species.
Until you actually start putting them on, one just cannot be sure how it will work. Cutting your own stock AS YOU GO allows you to "adjust" them as well, as opposed to having all your stock pre cut.
but oak...just no.
and yes "oregon" is just slang for doug fir...so if the store don't know this and one is cheaper??? keep it a secret!
personally, i'd rather have a ton of extra regular wood than just the right amount of perfect wood.
bruce

[Andrew2]

A friend bought a big bunch of Western red cedar in La Rochelle for a stripped planked 40ft cat, but it was a while back, came in 20ft lengths.
We buy Oregon pine/Doug fir in nice 6mtr lengths from a local yard in the Charente-Maritime 100x30 mm section, so you should be able to get it where you are. I am making my masts out of it. There is also sapin rouge, which I used for my last spars. Dunno what it is in english, but straight grained, no knots and fairly light, recommended by a local boat designer.

I am now trying to remember the wood a Dutch resident near Lyon used to strip (no glass over) his Ilur, who I met in the Morbihan at the 'fest in 07, he visited us later for a sail around the local waters here.

On ply, the same yard sells very nice void free ply It has hardwood outer lams and poplar inner. The glue is boil proof(tried that!) and it very well priced, around €60 for a 10mm sheet. Local friend is building a Sharpie 600 with it. Just put a light glass cloth (200gm)over to protect from scuffs.
A2