Abstract: A combination boat and trailer assembly movable on land and on water having outboard wheel assemblies and support structure therefor provided in integrated relation on the boat, wherein the wheels can be lowered to form a trailering system when it is desired to tow the boat and can be raised to positions withdrawing the wheel assemblies above normal water level when the boat is waterborne. The wheel assemblies each have a pair of pivotally intercoupled articulated rigid upper and lower arms and an interconnecting shock absorber located outwardly adjacent opposite sides of the boat hull and a ground engaging wheel rotatably journaled on the lower portion of the lower arm. The shock absorber resiliently maintains the arms substantially at an acute angle to each other and a rigid axle member extends from the upper arm through a pair of axially spaced bearing members aligned along a common transverse axis and supported by an inboard mounting structure.