tony.latham wrote:is well worth the weight savings and lack of rot.
Folks keep bringing up rot with wooden teardrops. It's malarky.
What can rot will rot. What is inert will stay inert.
I agree a properly built wood trailer can last if properly built. How do you know it is properly built though. Most people here are not professional builders. Foam gives you that extra bit of piece of mind knowing that if there is a leak (and there is not) that it wont be a expensive repair next spring.
I use OSB for my floors, 3 years and many a water crossing and still not soggy. It can't get soggy if it don't get wet for long periods of time. Why because it is protected by foam. Just my two cents...

Video of river crossing:
https://youtu.be/q03JboEM4o0?t=518