A system and method providing a portable, floatable vessel for controlling the absolute position and relative position and the motion of a floating craft using a small water plane area, high vertical drag coefficient and dynamic positioning is disclosed. The methodology employs a portable, floatable vessel that includes: a bridge structure, a lifting bridle connected to the bridge structure, a control center, first and second struts connected to the bridge structure, and first and second docking arms connected to the struts. The first and second struts are connected to first and second machinery pods with first and second azimuth thrusters for self-propulsion, motion control, and other operations while in water. Docking arms include drag dishes for stabilization and arm pods for buoyancy control of the docking arms. The docking brackets can firmly grip and stabilize the floating craft to minimize roll, pitch, yaw, and other motions of the craft during cargo transfer. The control center employs a dynamic positioning system for maneuverability and for controlling horizontal plane motion of the portable, floatable vessel.