Abstract: A variable-incline ramp system guides a vehicle through the incline between a first site and a second site while at all times maintaining the vehicle in its natural horizontal orientation. The ramp system includes a separate set of rails for guiding the front and the rear wheels of the vehicle. In profile, the two sets of rails form a parallelogram having one pair of sides of a length equal to the wheelbase of the vehicle. So long as these parallelogram sides are horizontally oriented, the vehicle traveling along the rails will maintain its normal orientation because its wheelbase axis will be parallel to the horizontal sides of the parallelogram. In one embodiment suited for use in marine settings, the rails are movably connected to the first and second sites such that as the site elevations change, the parallelogram is free to skew while still remaining a parallelogram with the same length sides.