A wheel pack assembly includes a pack portion wearable by a user, a wheeled portion removably coupled to the pack portion, and a power assist system. The pack portion includes a first interfit element. The wheeled portion includes a frame, a second interfit element coupled to frame and configured to removably couple with the first interfit element of the pack portion, and a first wheel set coupled to the frame and disposed at a location spaced apart from a rear end of the wheeled portion. The power assist system includes a motor mechanically coupled to the first wheel set, at least one sensor coupled to the at least one of the first interfit element and the second interfit element, and a controller configured to operate the motor based on feedback from the at least one sensor.

A vessel for transporting cargo has a first hull and a second hull that are slidably coupled together to be movable between an extended position and a retracted position that is shorter in length. Wheels are coupled to the vessel. The wheels can contact an underlying surface of the vessel when the vessel is oriented at an acute angle relative to the underlying surface. The wheels are free of contact with the underlying surface when the vessel is parallel or substantially parallel to the underlying surface.