Yes all those boards will suck water if the foam is exposed.

Have fixed a couple of Naish's before and they do suck water.

Just leave it out in the sun and the water should bubble out.

The surftech foam is no more porous than what you would find in a regular PU board as far as I know and from experience with these. Not too sure on the others but seems a strong correlation between price and quality of materials. I think some of the cheapies that you see on the ebay etc have a more budget and open cell styrene.

Pretty standard windsurf (similar construction) experience is to have an epoxy "dingstick" in the car. These are rolls of epoxy paste, you just tear/cut off a bit, knead it till it's consistent colour then bog up the hole - you can be back on the water in about 10 or 15 minutes. It's a real bugger when water does get in and really worth doing the board lady vacuum thing or at least really cutting away the affected foam and doing a proper repair. If you don't fix it properly it stuffs the board because the foam continues to break down.

Any boards that I've ever had water in I always leave the plug out whenever the board is not on the water, store the board flat up the normal surfing way and the water vapour bubbles out of the plug hole - if you put your ear to the plug hole when the board is hot your can hear the crackle of the water bubbling through the foam.
Problem then is that from then on you always have to remember to put the plug back in - I actually tie something bright coloured to the leg rope tie when I undo the plug so I don't forget to tighten the plug before I go out, otherwise I spend the whole time trying to remember whether I did the plug up or not!

Thanks to all for the valuable info.

Hey Rod, Howard Hughes told me a similar thing, he suggested covering the foam with 5 minute araldite, then, when hard, fixing with normal fibreglass and polyester resin. Works for me.
Robdog