A deployable platform is disposed at a side of the hull of a marine vessel and is movable between a raised position in which the platform is substantially vertically oriented, and a first lowered position in which the platform is in a horizontal orientation. Further, at least a portion of the platform can be lowered to a second lower position that is below the first lowered position. In the second lowered position the platform will normally be submerged when the vessel is afloat in water. In the raised position the platform forms a portion of the side of the hull and acts to exclude water from entering the vessel.