Recreational watercraft and methods of operating recreational watercraft are described. Recreational watercraft can include an aluminum hull, a plurality of ballast tanks, a first surface defining a first opening that extends from an interior of a ballast tank of the plurality of ballast tanks to an exterior of the hull, a valve configured to selectively open or close the first opening, and a second surface defining a second opening that is fixed permanently open and extends from an interior of the ballast tank through a bottom portion of the hull to an exterior of the hull.

Recreational watercraft and methods of operating recreational watercraft are described. Recreational watercraft can include an aluminum hull, a plurality of ballast tanks, a first surface defining a first opening that extends from an interior of a ballast tank of the plurality of ballast tanks to an exterior of the hull, a valve configured to selectively open or close the first opening, and a second surface defining a second opening that is fixed permanently open and extends from an interior of the ballast tank through a bottom portion of the hull to an exterior of the hull.

Recreational watercraft and methods of operating recreational watercraft are described. Recreational watercraft can include an aluminum hull, a plurality of ballast tanks, a first surface defining a first opening that extends from an interior of a ballast tank of the plurality of ballast tanks to an exterior of the hull, a valve configured to selectively open or close the first opening, and a second surface defining a second opening that is fixed permanently open and extends from an interior of the ballast tank through a bottom portion of the hull to an exterior of the hull.

A cargo hold having a plurality of spaces, which are formed by a longitudinal bulkhead and a transverse bulkhead intersecting each other and store crude oil, comprises a void space located at least one corner among corners formed by intersection of the longitudinal bulkhead and the transverse bulkhead, wherein the void space is formed of a void space structure having one side end and the other side end sealed by and fixed to the longitudinal bulkhead and the transverse bulkhead, respectively, thereby forming an empty space inside the bulkheads. The vessel cargo hold prevents a danger, such as fire and explosion, which may occur during the maintenance or repair of the vessel cargo hold for storing crude oil, and decreases work or the like required for the maintenance or repair of the cargo hold.

A cargo hold having a plurality of spaces, which are formed by a longitudinal bulkhead and a transverse bulkhead intersecting each other and store crude oil, comprises a void space located at least one corner among corners formed by intersection of the longitudinal bulkhead and the transverse bulkhead, wherein the void space is formed of a void space structure having one side end and the other side end sealed by and fixed to the longitudinal bulkhead and the transverse bulkhead, respectively, thereby forming an empty space inside the bulkheads. The vessel cargo hold prevents a danger, such as fire and explosion, which may occur during the maintenance or repair of the vessel cargo hold for storing crude oil, and decreases work or the like required for the maintenance or repair of the cargo hold.

An oil container of a combustion engine. Oil collected in the oil container can be, conveyed to the combustion engine and back into the oil container, having a central oil chamber out of which oil can be suctioned and lateral oil chambers positioned either obliquely above or obliquely below the central oil chamber depending on an oblique position of the oil container. Oil is directed to the lateral oil chambers from the combustion engine, and, depending on the oblique position of the oil container, the central oil chamber can be coupled to a first lateral oil chamber that is adjacent to the central oil chamber on a first side of the central oil chamber, or to a second lateral oil chamber that is adjacent to the central oil chamber on a second side of the central oil chamber, via a respective passively controlled check valve.

A dual-fuel tank houses one or more compressed natural gas (CNG) vessels and one or more diesel fuel vessels. The diesel fuel vessels are generally disposed laterally outwardly from the CNG vessels to provide a buffer that protects the CNG vessels from side impacts. The dual-fuel tank may be retrofit onto a diesel locomotive in place of the locomotive's diesel fuel tank to convert the locomotive into a dual-fuel locomotive. The dual-fuel tank may be provided in a ship.

A dual-fuel tank houses one or more compressed natural gas (CNG) vessels and one or more diesel fuel vessels. The diesel fuel vessels are generally disposed laterally outwardly from the CNG vessels to provide a buffer that protects the CNG vessels from side impacts. The dual-fuel tank may be retrofit onto a diesel locomotive in place of the locomotive's diesel fuel tank to convert the locomotive into a dual-fuel locomotive. The dual-fuel tank may be provided in a ship.

The subject invention is a design of marine cargo vessel with added mechanical equipment specifically designed to minimize dangerous motions of the vessel induced by high waves while the vessel is being loaded or unloaded from fixed platforms (bottom supported or tension leg) at sea or on inland waters. The vessel uses three means of reduction of such induced motions, which have not before been combined for this purpose. These are a small water plane area multiple hull design, rapid ballasting while loading and unloading, and vertical thrusters.

The subject invention is a design of marine cargo vessel with added mechanical equipment specifically designed to minimize dangerous motions of the vessel induced by high waves while the vessel is being loaded or unloaded from fixed platforms (bottom supported or tension leg) at sea or on inland waters. The vessel uses three means of reduction of such induced motions, which have not before been combined for this purpose. These are a small water plane area multiple hull design, rapid ballasting while loading and unloading, and vertical thrusters.