| But since you seem to have decided that you want to build the boat with cheaper core please do so and if you survive tell us how it went.

Just to clarify, I just asked questions. The math/boatdesign.com suggested the 'cheaper foam' is adequate for big parts of a HP, which has large parts of the boat lightly stressed, and he is looking at samples of the 'cheaper foam', imported from abroad, to see if they meet his standards for the lightly loaded parts of the boat, and I am building kayaks out of it to get a better understanding of it's practical performance.

The amazing part, to me, is Rob vigorously engaged the idea of a core substitution. Moving from 'I tried this, it does not work' to 'I think this is impressive, but let me run tests'. I got to ask if anyone knows another designer so open minded?

I, as is only reasonable, fully expect to build all of my boat out of recommended foam. I don't see myself ignoring Robs recommendation in any case. I may be a test case, but I am alright with that.

If you have any objections to my current plan, I am all ears. I would rather learn from your experience. It is way cheaper than the alternatives.

And, I will note again, this XPS thing is because for me, in the US, this foam is cheaper, and comparable. Bjorn is in the same boat (ha) in his country. Rob's willingness to engage makes HP's easier to build for budget builders all over the world. I also think it leads to a deeper understanding of boats.

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