Building my first HWS, a 9.0, 30", 4" 145 litres fat SUP. Having a bit of a brain freeze with the method of doing the rails, and thought about “reverse compsand”, adding maybe 10 cm wide blocks of PU between the ribs and shaping them to shape.
Pros / Cons I thought about
Any thoughts on this idea?
Hi Michi,
I’m not shure if i got it right, but I guess I did something similar with xps, check out http://www2.swaylocks.com/forums/62-hollow-poplar-xps-surfboard?page=2.
It is easy, shaping is fun, yes it is light but you have to make shure there’s enough layers of glass in the rail area.
Hi Florian, yeah pretty much like that was the idea!
There’s also the question of doing full rails like you did, or use separate blocks between the ribs of the skeleton. One way to do it could be to make slots in the foam for the end of the ribs, but don’t know if that’s a working solution.
A hollow wooden rail would be the best I guess, but I don’t have the right tools and especially not the right skills for that 
…
My guess is that with separate blocks of foam the rail is not so easy to shape if there are many glue lines. You would have a glue line every foot at least (depending on distance between the ribs). If you just make small slots for the ribs, you would avoid the glue lines. Concerning the stiffness: many HWS are considered to be too stiff anyway, so foam rails wouldn’t hurt.