When someone uses a thing unwisely it doesn't automatically become a bad thing. Used correctly, pour foam is awesome. It adds both strength AND flotation, and what's not to like about that? Here's the short deal for those who don't want to watch the whole video;
* Pour foam expands. A lot. Use in an open area only. C'mon man!
* Pour foam contracts again slightly as it hardens, and will distort a thin flexible surface. Best practice is to use in wood boats only.
* Pour foam will not 'react again' (the little atom buggers become different atom buggers during the initial reaction and cannot switch back).
* Pour foam will not absorb water when cracked. The reaction creates a kazillion tiny bubbles, not one giant bubble that would lose its bubblyness if cracked. Let's use some common sense here. See c'mon comment above ^^^
* Pour foam does not become squishy when wet. On the contrary, it is brutally hard and will remain so indefinitely.
* Pictured here is a way to make your boat very strong and very floaty (is that a word?).
* This boat pictured is four years old, looks like new, was nitro, now electric, won last weekend.
* Go build a boat!