Making a new seat for Waveline RIB

[MoodySabre]

Job from my son.

The seat has broken in the middle - it's got two bits of ply inside the plastic/fibreglass covering (each half the length of the seat) and not one - a design fault. Hey ho. It's 85cm x 20cm.

I don't have the gear (or the desire) to start glassing in a new bit of ply even if i could find a bit the right size.
I could just buy a new one £37 +P&P http://www.ribstore.co.uk/shop/product.php?productid=432&cat=73&page=1

Is there a sufficiently strong plastic board from which I could make one? Would non-marine ply with loads of varnish last long? I have an old mahogany shelf that would be big enough but very heavy.

 

[FullCircle]

Roger a piece of WBP Plywood would last for years (not as long as Marine Ply)

Sapwoods in Ashingdon Rd would cut you a piece of 19mm thick for less than a tenner.

Slosh the varnish on.

Don't be tempted to use shuttering ply - its carp.

 

[MoodySabre]

Thanks Jim - will forage in the Leigh Timber off cuts bin and then Sapwoods.