Hmm...
Good rubber 4-ply exhaust hose is a little stiff, but a heat gun eases it...silicone grease helps it..and it is extremely tough. Think about what it is used for! It's also, as far as I know, the standard and ABYC-recommended material for the job you are doing. Comes in lots of sizes...and, in fact, the original Pearson hoses were--guess what?
It is also worth considering in all this...that you don't want to go horsing on the fiberglass tubes harder than needed. Also, for the same reasons that it is important to have hose in there in the first place (production concerns aside)---the flexing of the sole, and the flexing of the hull (both are more than one would likely think)--you do not want an excessively stiff hose in there.
Does this yard do engine work/installations? Then...they should have the proper exhaust hose in inventory.
Not to seem contrary, but it sounds like a lot of wheel reinvention to me.
Dave
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