The present invention provides, with reference to FIG. 2, an amphibian operable in land and marine modes, the amphibian comprising a hull, at least one discontinuity (wheel bay) provided in the hull, and at least one retractable wheel or track assembly at least partially located in the at least one discontinuity (wheel bay). The hull is a planning hull, and the at least one discontinuity (wheel bay) is provided in the front half of the hull of the amphibian. The amphibian further comprises at least one conduit which opens, or is provided with an entry which opens, into or at the at least one discontinuity (wheel bay) and is configured for channeling, in use, fluid away from the at least one discontinuity (wheel bay).