An improved system and method of storing water for a closed-loop pumped storage hydroelectric system is provided. The method includes providing a floating reservoir, positioning the floating reservoir in a waterbody, loading the floating reservoir with a volume of water from a source other than the surrounding waterbody, and transferring water from within the floating reservoir to an upper or lower reservoir of a pumped storage hydroelectric system. The floating reservoir includes a flexible membrane defining one or more reservoir cells including a vertically collapsible sidewall, such that each reservoir cell defines a depth varying in proportion to its internal volume of water. Each reservoir cell is buoyed by pontoons adjacent an outer periphery of the reservoir cell and is anchored to the shore or streambed.

An autonomous body of water navigation system and method uses the current of the body of water. The body of water navigation method may be asymmetric since cargo may be transported along with the current of the body of water and the navigation system can be easily transported back up the body of water.

A towed vessel suitable for containing and transporting various liquids is disclosed. The vessel further comprises various features useful in the transportation, navigation, and storage of the towable vessel, both when in use for transporting fluids and when transported in an emptied state. Such features include navigational and positioning devices and methods, power supply devices and methods, and means for filling, inflating, emptying, and deflating a non-rigid, towed vessel. Aspects of embodiments of the present invention further include features useful for purifying or preserving the purity of the fluid to be transported.

A towed vessel suitable for containing and transporting various liquids is disclosed. The vessel further comprises various features useful in the transportation, navigation, and storage of the towable vessel, both when in use for transporting fluids and when transported in an emptied state. Such features include navigational and positioning devices and methods, power supply devices and methods, and means for filling, inflating, emptying, and deflating a non-rigid, towed vessel. Aspects of embodiments of the present invention further include features useful for purifying or preserving the purity of the fluid to be transported.

An autonomous cargo transporting system transports the cargo on a body of water using the natural current of the body of water to deliver cargo to a downstream port. The cargo system is asymmetric since cargo is delivered downstream using the current but the cargo system is disassembled (drastically reducing the weight) for a multimodal return trip back up the body of water.

A method for delivery of drilling fluid to a seafloor drilling assembly, the method comprising the steps of filling at least one container with drilling fluid; lowering the container through a body of water to adjacent a seafloor drilling assembly; connecting the container to the seafloor drilling assembly to deliver drilling fluid to the seafloor drilling assembly.

A subsea material delivery structure, including at least one material storage tank, wherein the material storage tank includes a rigid outer container, at least one pressure balanced inner flexible container. A pinch prevention device may be disposed within the at least one inner flexible container to prevent premature closing of a fluid egress pathway.