I've just had a sprayhood extension made by Quay Sails of Poole, which might be of interest. Very simple and it does work, as it poured down the day I first fitted it. It is fixed to the boom gallows I built a couple of years ago, which is an addition I keep singing the praises of. The extension's aft edge slides into a track on the forward face of the gallows, and it is stored by simply being rolled up under the gallows, so it is always to hand. I fitted a GRP tent hoop across at mid point, as it sagged somewhat without. Two tapes pull it forward to tension it, but I am not sure they are really needed. A bit of experimentation will determine that. I had thought of having a zip fitted to the sprayhood, but Quay Sails felt that would be overly complicated, and I think they were right. The photos should make it clear, I hope. It keeps the great bulk of the cockpit covered, and you can climb in and out from the stern, without having to undo the bungies that hold down the corners.