caulking

The board is slotted into a groove packed with sphagnum moss and beeswax, the moss is dried out over the fire and then expands when it gets wet to increase the waterproofing. There is another board pegged over the top to prevent the transom from rising up as the boat dries out. The semi circular projections carved in the bottom of the boat are based on similar features in the Late Bronze Age dugout found in the river Tay estuary at Perth a few years ago. These are supposedly unique features and have been interpreted as foot-rests to stand on when punting.