That sounds like a good compromise.  Use each material where its strengths will matter the most.

  Since I won't be making my own hulls, I don't care about the workability of the material, so the foam below the waterline is less of a draw for me.  I'm personally more concerned about the core's response to trauma than to its ability to resist water intrusion.  But that's splitting hairs.  People use good foam for a reason, and there's nothing wrong with it.

  I'll definitely buy the argument for foam beneath the waterline.  Foam decks would seem to be less of a draw.  You really can plan and seal your penetrations on deck, and there's definitely less exposure to water.

       - Mike

 

Gardner Pomper wrote:

Hi,

I don't think the test is particularly scientific, but I would be interested to try it myself, although I don't think that boiling the water is quite correct. I would use steaming hot, but not boiling. I think I will also immerse a piece of honeycomb in room temp water for a week to see what that does.

I think your explanation of why the water migrates in this test is probably correct. The question is how susceptible is the honeycomb compared to balsa, for example. Water migration is not an all or nothing thing.  That is why I am looking for feedback from people who know more than me about it.

Btw, Derek says that this is the test he uses on all his core materials, so apparently the foams he uses pass that test.

You also did not mention the biggest factor for me.. the price of honeycomb vs foam. From what I see, honeycomb is about 1/4 the price, and since the core is the most expensive material in the boat, that make a HUGE difference in the materials cost.

I don't see Dereks test ruling out honeycomb, the way he does, but it does raise questions for me about whether I should use it everywhere. I have already been thinking that it might be good to use a flexible airex foam for the keel sections where the big flat panel needs to bend, with honeycomb for the hull topsides. Now I am wondering if maybe I should use foam on some or all of the decks, like where the various cleats are mounted, just in case.

- Gardner

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