Many of the terms used for parts of the skiff are of Germanic origin – "", "thwarts", and "". Planks on either side of a wooden keel are laid down following the outline of a sham (temporary pattern) placed across the keel. The planks are nailed in place and then a transverse strengthening framework of ribs is added. Oars (or blades) are held in place by wooden thole pins at the side of the boat rather than rowlocks or outriggers. The thole pins are designed to give way if too much pressure is put on them, thus protecting the boat itself from damage. The thwart, or seat, is fixed rather than sliding as in modern boats. The sax runs round the top of the boat to strengthen and protect it. Blades are made of wood with leather collars.