Hi mattaipan!
I feared the wood wouldn't be the problem - I was trying to work out where an extra 3kgs would be, and I can't see the deck weighing more than 2kg. To be honest, I was hoping I'd have more luck inside - she seems somewhat overengineered to my tastes, and while I want a strong hull, I suspect that I can make better use of materials to drop the weight down a bit. I wasn't expecting to see so much wood inside the hull - although it may be simply that I don't know what I'm looking for. The lapstrake hull we're building has no internal structure, and my other OTB cat - also in need of work - is made from aluminium, so the hulls are completely empty.
Whatever happens, I'm leaning towards replacing the deck, but that may be because I'm foolishly sold on the idea of a bright finish.
Thanks heaps for the advice. Work has meant that I had to delay the project, and will probably miss the whole of this season, but I'm finally able to get started. It should be fun.