Starting at either end, slowly pull the two hull halves together until the ends of the top planks are touching. Holding a small spring clamp in one hand, pinch the two plank ends together with the other hand. Line up the planks so that their bottom edges are even and clamp them together with the spring clamp. Put the clamp near the top edge of the plank; don't worry about the gains at the moment; they will be clamped in the next step.