Foam Core Construction

[TexasRiverRacer23]

Are any of you very knowledgeable with foam core and composite layups?

I built a solo canoe years ago using 3/8” thick Corecell foam that was skinned inside and out with Kevlar and an extra layer of fiberglass on the exterior. It was an extremely tough boat and fairly light but I want to go lighter. It ended up fully rigged around 38-39 lbs and I want to drop the weight to around 30.

I would appreciate any input on what core thickness and material combinations you would recommend for the toughest yet lightweight boat possible for long distance marathon races. 60-340 miles

I’m trying to research and learn more about core layup construction but still have a lot to learn.

Thanks for any information. This is the boat which you may have seen in another thread.

 

[Jim Dodd]

Just a few thoughts from my limited experience.

Two layers of Kevlar, inside and out is over kill, in my opinion.

Go with S-glass for at least one of those layers. Sweets composites only has 4 oz, in 60" widths.
https://sweetcomposites.com/ They may be able to help more with a lay up selection.

An extra layer over the football would add durability, and stiffness.

I used 4 oz, S-glass on my last stripper. I cannot verify any weight savings yet, as I'm at the trim stage now.
I used thinner strips this time also.

Stripper guy has some great info on foam selection !

Jim

 

[Glenn MacGrady]

I am not a builder and don't have personal knowledge of the different foam core materials, but here is a technical article:

Foam Core Materials in the Marine Industry

I also know that John Diller at Savage River builds 18+ foot racing canoes in the 20-26 lb. range in a variety of layups described on his web pages:

Racing C-1

C-1 / Asymmetrical - Marathon Racing / USCA Competition Cruiser - Length: 18' & 18'6 - Weight: 20-26 lb

www.savageriver.com

The detailed descriptions of his various layups suggest that Diller uses foam cores and ribs, but I don't see a statement about exactly what kind of foam he uses. One well-known marathon racer, Marc Gillespie, comments on one page that: "The foam core you use is far superior to the Hexcel, especially since it can be heated to regain its shape." I suppose you could just call Diller and inquire about what foam he uses.

 

[ppine]

Wenonah has used a lot of foam core in the interest of saving weight. I crunched one of their boats in a Class I rapid and was shocked at the amount of damage. You can build light boats or strong boats, but it is exceedingly difficult to build both at the same time.

 

[TexasRiverRacer23]

Here is a link to the last foam core hull I made. The link may take a while to load. This is part 2 but shows how I did the foam. It will have links to part 1 and 3.

Duckworks - 50th Anniversary Boat Build - Part Two

That boat ended up being super tough. I pinned it badly in limbs from a fallen tree in the river and the boat completely submerged. It took 5 or 6 of us to get it out and I fully expected it to break in half but fortunately it didn't. Minor damage all things considered.