Embodiments include a retrofit pontoon system including a pontoon, the pontoon having a pontoon body defining a first cavity, the pontoon body having a first aperture; a retrofit assembly, the retrofit assembly including a selectively fillable container sized to pass through the first aperture; and a pump. The pump is operably coupled with the selectively fillable container such that operation of the pump selectively fills and drains water from the selectively fillable container, wherein filling the selectively fillable container lowers the profile of the pontoon in the water and emptying the selectively fillable container raises the profile of the pontoon in the water.

Embodiments include a retrofit pontoon system including a pontoon, the pontoon having a pontoon body defining a first cavity, the pontoon body having a first aperture; a retrofit assembly, the retrofit assembly including a selectively fillable container sized to pass through the first aperture; and a pump. The pump is operably coupled with the selectively fillable container such that operation of the pump selectively fills and drains water from the selectively fillable container, wherein filling the selectively fillable container lowers the profile of the pontoon in the water and emptying the selectively fillable container raises the profile of the pontoon in the water.

A ballast and de-ballast system and method for an articulated tug barge (ATB) or integrated tug barge (ITB) are described herein. The system includes a tug ballast tank located on the tug, the tug ballast tank being configured to hold ballast water; and a barge trim tank located on the barge, the barge trim tank being configured to hold ballast water. The system further includes at least one umbilical line connecting the tug ballast tank to the barge trim tank. The system is configured to transfer ballast water between the tug ballast tank and the barge trim tank via the at least one umbilical line.

A method for energy generation includes receiving, at a carbon negative energy generation system, input including calcium oxide and water and reacting, within a reaction chamber of the carbon negative energy generation system, the calcium oxide and water to release energy and generate calcium hydroxide. The method further includes directing, by the carbon negative energy generation system, the released energy to facilitate propulsion or onboard electricity generation and dispensing, by the carbon negative energy generation system, the calcium hydroxide into the ocean to sequester atmospheric CO.sub.2.

A method for ship ballasting includes receiving, at a carbon negative energy storage system, input comprising calcium oxide and water and reacting, within a reaction chamber of the carbon negative energy storage system, the calcium oxide and water to release energy and generate calcium hydroxide. The method includes directing, by the carbon negative energy storage system, the released energy to a requesting end user and providing, by the carbon negative energy storage system, the calcium hydroxide to a marine vessel ballasting system. The method includes releasing a mixture of the calcium hydroxide and ballast water from the marine vessel ballasting system into the ocean to sequester atmospheric COCO.sub.2.

A semi-submersible spar-type offshore fish farm (1) for cultivating fish at open sea, including an elongated center column (2) that includes a first end part (3), and a ballast system (4) that is arranged at the first end part and that includes at least one buoyancy tank (5) and at least one clump weight (6) that are movably interconnected, wherein in use of the fish farm the at least one buoyancy tank and the at least one clump weight are arranged at a distance, D, with respect to each other.

A reverse osmosis water production apparatus for use in a body of water includes a first section defining a buoyancy chamber and an elongate second section connected to the first section and configured to define an elongate chamber which extends downward beneath a waterline in use. The elongate chamber is provided with a plurality of elongate reverse osmosis membrane tubes, each tube containing a reverse osmosis membrane. A longitudinal axis of each reverse osmosis membrane tube is substantially parallel with a longitudinal axis of the elongate chamber and the reverse osmosis membrane tubes are arranged around a passage.

A reverse osmosis water production apparatus for use in a body of water includes a first section defining a buoyancy chamber and an elongate second section connected to the first section and configured to define an elongate chamber which extends downward beneath a waterline in use. The elongate chamber is provided with a plurality of elongate reverse osmosis membrane tubes, each tube containing a reverse osmosis membrane. A longitudinal axis of each reverse osmosis membrane tube is substantially parallel with a longitudinal axis of the elongate chamber and the reverse osmosis membrane tubes are arranged around a passage.

Wakeboat fluid housing compartment fluid level sensing assemblies are provided. The assemblies can include: a wakeboat having a hull; a fluid housing compartment associated with the hull; a nonconductive sensor chamber positioned within the fluid housing compartment of the hull; and at least a pair of conductive electrodes associated with the sensor chamber, at least one of the pair of conductive electrodes being positioned within the nonconductive sensor chamber and electrically isolated from fluid within the fluid housing compartment. Methods for sensing a fluid level within a fluid housing compartment aboard a wakeboat are also provided. The methods can include: maintaining fluid communication between the fluid level within the fluid housing compartment and a sensor chamber; and determining the electrical communication between at least a pair of electrodes operatively associated with the sensor chamber.

The present disclosure provides power source assemblies aboard a watercraft. The power source assemblies can include: an engine having a crankshaft; a variable ratio drive assembly operably engaged with the crankshaft; and an engine powered accessory operably engaged with the variable ratio drive assembly. The present disclosure also provides methods for distributing power aboard a watercraft from a crankshaft of an engine. The methods can include: using a crankshaft of an engine to drive a variable ratio drive assembly; and using the variable ratio drive assembly to drive an engine accessory over a narrower RPM range while operating the crankshaft over a wider RPM range.