V-21 Transom

[chesapeake724]

I don't know the answer, but my bet would be on wood.

If I might get on the soapboax a little, wood makes a great core material and I'd never stay away from a boat because it was built with wood coring. The catch is, that all the wood must be properly encapsulated in fiberglass and otherwise completely sealed from water, including screw holes, limber holes, etc. That is a function of the build quality of the manufacturer, not the physical properties of the wood itself.

Just my two cents...stepping off my soapbox now. ;)