Speed Strip tongue-and-groove strip planking

[wardd]

table router?

[Willallison]

Bearing in mind that it was a couple of years ago, here are the standard retail prices I was quoted, by Highpoint Timbers in WA.

42x19 $2.15 inc GST per LM
30x19 $2.15 inc GST per LM
19x19 $1.76 inc GST per LM

We can take the thickness down to 6-mm. We can also do a concave convex or a tongue and groove profile for an extra cost of $10.89 inc GST per m2.

That works out to more like $2700 /m^3 + GST

[rwatson]

The last prices I got a few weeks ago were
42mm x 12mm = $2.15 per lineal metre

My bad math calculated this at $4265 per cubic metre, and according to those calcs you are right, your prices were about $2700 per m3.

No wonder they didnt ring me back to confirm the price per cu metre.

I bet Western Red Cedar isnt so exhorbitant

[Willallison]

I haven't priced WRC for some time, but I believe it's about 30% more than Kirri
Further - In reality, the cost of the timber in a project of reasonable size is going to be a small proportion of the overall cost. In the case of my most recent build it amounted to approx 1% (including the professional labour)

[rwatson]

yeah, well if you are building big boats, timber may be a small percentage allright, but for smaller boats, its still a big component.

Even more importantly, it makes foam/resin construction much more competitive.

Looks like the days of wood construction are nearly over. As far as strip planking construction goes, considering the labour intensitivity, it will become a thing of the past as well.

[Willallison]

The particular example to which I referred is 32 foot overall (pictured below). I don't regard it as a particularly large boat, but I guess that's just a matter of opinion.

As a rough approximation, FRP clad Kirri would cost around $100 / m^2, Foam panels (Duflex) cost about $200 / m^2. The time involved in building and fairing would depend very much on the project in question. But the reality is that labour is by far the largest component. For the home-builder, that obviously isn't a concern.
Strip planking is actually a very quick way of producing a complex one-off shape, and of course there are any number of decisions that go into the choice of building materials and methods, not just price.

I disagree... I think that there will always be a place for wooden boats and a significant proportion of those will be strip-planked

[rwatson]

yes, I agree for complex shapes, strip is good. I plan to do the chines on my 28 footer in strip, but the rest in foam/epoxy.

I dont follow your costings though. At the quoted prices for Kiri, they work out at around $50 per m2 without FG. Airex, Klegecell core material etc vary between $48 and $60 per m2 without FG, and they come in much bigger sections that dont need gluing together, dont absorb water as much as timber, and cant rot.

I love timber as much (if not more than) the next man, but I cant think of a good commerical reason to build in timber at this point.

[Willallison]

Sorry - that wasn't very clear...
I was referring to the cost of off-the-shelf foam or balsa panels with FRP skins, which are typically about $500 per sheet, depending on thickness, density, and skin thickness. I employed these for almost everything except the hull shell in the boat above. CNC cut, they can drastically reduce the amount of time involved in construction. They have their limitations, of course, and one needs to be very aware of the time, effort (and weight) of fairing them to a standard such that they can be painted.
Of course, if you're using them where there's significant curvature, or if the shapes aren't deveolpable, then the norm would be to do as you suggest and simply glass over foam panels.
It's important to consider the added weight that filling all the kerfs can add to the structure too. It's also a mistake to think that water can't migrate through the core. There's been a few very good articles in Professional Boatbuilder that dispell that myth. Yes, of course closed cell foam is far better in this respect than many other materials, but it's not immune.

[Willallison]

One other point to consider. When I did the materials selection for Graphite, I considered a number of construction choices. Strip plank and foam core were the two I narrowed it down to. In the end, strip-plank got the nod partly for cost reasons, but mostly because it was actually lighter than the foam core equivalent. The foam core itself would have been lighter, but would have required much heavier skins for strength and impact resistance