Abstract: A trailer assembly, including: (a) a frame sub-assembly, wherein the frame sub-assembly comprises a pair of rails adapted to support a pontoon/tritoon watercraft thereon; (b) at least two ground-engaging wheels, wherein the at least two ground-engaging wheels are associated with the frame sub-assembly; (c) a trailer coupler, wherein the trailer coupler is releasably securable to a trailer ball; (d) a rail drive sub-assembly, wherein the rail drive sub-assembly comprises a battery, an electrically powered hydraulic pump, at least two actuating hydraulic cylinders, and an up/down controller; and (e) wherein the trailer assembly is readily convertible between a raised position and a lowered position.