wood-free strip-plank?

Foam strips are typically used as a core with fiberglass or similar on both the inside and outside which provides the strength and stiffness. I'm not aware of any foam which can be used without structural laminates on both sides. Wood strips can provide the strength and stiffness without fiberglass or similar.

 

I see what they did there!

 

I know of four 12 meter sailing cats built by laying up full length panels of foam (12 meter) with light UNI Glass each side, on flat table.
Rip into strips ( width dependant on hull curvature) as per timber strip plank method.
Plank forms as per timber strip plank method .
Glass inside and out as per timber strip plank method.

Down side is you have to work neat and accurate as you can't sand the planking fair before glassing
ie no different from ATL composite balsa strips.

 

AIREX, Coosa Board, Corecell, Divinycell or Thermo-Lite Board
Would none of these be suitable?

 

They are suitable for various purposes, perhaps you should indicate the boat you want to build, or an approximation of it, so people know what you are aiming at.

 

Obeche (Triplochiton Scleroxylon, Ayous, Samba & Wawa) has the same weight as WRC but is not rot resistant. Grows in SA and other african countries so in theory should be available and not to expensive. Of course you have to investigate what is cheaper for you, wood/epoxy or foam/polyester. The designer will specify the type and density of the foam (I believe there are some domestic foam brands in SA?). If the design is specified for wood/epoxy you have to ask the designer for a conversion to foam and new scantlings.
The actual work with the foam depends on the shape to be planked, but it's not more difficult then strip planking.

 

The designer needs to specify the core, so the conversation is mute to some degree. But many core boats use strip planking methods where curvatures are required. Some fairing of the strips is possible, but just like wood strip; it is tricky because the glue joints are much harder than the foam. So the foam will sand faster than the joins.

The top of these steps was made with foam strips about 1" wide. 12mm core

 

Also, important to realize cost goes up for foam. You need more glass and epoxy than wood boats require. Roughly double the cost. Typically foam is more money than wood. So, you are not saving money.

 

For the purpose of this discussion, use the Bowdidge Riptide or Cruise Control as an example.
RipTide XR-457 https://bowdidgemarinedesigns.com/riptide-xr-457/
Cruise Control 5.2 https://bowdidgemarinedesigns.com/cruise-control-5-2-2/

Both designs are strip plank composite construction

 

Looks like a lot of work in making one of those. What particular skills do you have, word-working or...…. ?

 

They are largely dev panel. So, some of the panels are kept pretty big and some strip work is done. Big question is how is laminating the glass done? Infusion or just hand layup or panels.

personally, I might prefer wood construction as the glasswork would be simpler most likely

i was writing when Mr E posted and we had a shared notion of might be lotsa work

 

Lotsa work in foam, that is...

the callout for wood and plywood is easier and right because the glass needs are so much less...

 

It is unlikely the designer would modify those designs to foam. I would be rather surprised.

He might, but the work would be above most amateur abilities.

And the boat I have pictured is all foam, but simpler than those two hulls..and built in a female mould; not male.

I could be wrong. It starts with him, though; not us.

The trouble for foam constuction os the male station system he uses will not keep a foam hull true on flip for internal glasswork. And so, you need to build it differently...likely with a female mould.

 

Very true, and something glossed over at times. You need a proper cradle to hold the thing to the shape, and that is another substantial job.

 

A foam boat is more
commonly built with panels prefinished (glassed) and then bonded together or infused as a whole on the inside. Here is a female station setup for the hull I pictured. This setup allows the foam bulkheads to be installed before the boat/hull is flipped for external work.. Credits to designer Richard Woods