Abstract: A boat hull having a bow (11), a stern (12), a bottom (14) extending between the bow (11) and stern (12), a deck (15) and a space under the deck (15) between the bow (11), stern (12) and bottom (14) which provides buoyancy for the hull, the space above the deck (15) being bounded by bulwarks (16) which surround the deck (15), at least one panel (18) located to one side of the hull which is hingedly supported about an axis (19) substantially parallel with the deck (15) to be movable between a first position at which the panel (18) forms a portion of the side of the hull and at least a portion of the panel (18) forms a part of a bulwark (16) and a second position at which the panel (18) extends outwardly from the side of the deck (15), and is rigidly retained in the second position, said panel (18) being buoyant.