A pump-less buoyancy engine for an autonomous underwater vehicle (AUV) includes a buoyancy reduction structure without a hydraulic pump for reducing the buoyancy of the AUV to cause the AUV to descend in the water; and a weight dropping structure for dropping prepackaged weights out of the AUV to cause the AUV to ascend in the water, where the AUV moves forward when descending and ascending.

A subsea carrier (100) for transporting a fluid, e.g. CNG or crude, comprises a main body (101) for containing the fluid at a predetermined internal pressure, wherein the main body (101) preferably is made of concrete and designed to operate at a water depth where the external pressure substantially counteracts the internal pressure. The subsea carrier has a floating element (102) connected to the main body (101) by a stabilising cable (132), wherein the stabilising cable (132) comprises a first rope (321) for transmitting force and is attached to a first connector (134) that is movable with respect to the main body (101). A system wherein the subsea carrier is towed by a surface vessel (3) or is self-propelled and controlled remotely is also disclosed. The subsea carrier (100) reduces operational costs relative to subsea carriers with traditional control surfaces and ballasting systems at large cargo volumes, e.g. 150 000 m.sup.3 or more.

A subsea carrier (100) for transporting a fluid, e.g. CNG or crude, comprises a main body (101) for containing the fluid at a predetermined internal pressure, wherein the main body (101) preferably is made of concrete and designed to operate at a water depth where the external pressure substantially counteracts the internal pressure. The subsea carrier has a floating element (102) connected to the main body (101) by a stabilising cable (132), wherein the stabilising cable (132) comprises a first rope (321) for transmitting force and is attached to a first connector (134) that is movable with respect to the main body (101). A system wherein the subsea carrier is towed by a surface vessel (3) or is self-propelled and controlled remotely is also disclosed. The subsea carrier (100) reduces operational costs relative to subsea carriers with traditional control surfaces and ballasting systems at large cargo volumes, e.g. 150 000 m.sup.3 or more.

Generally, the present disclosure relates to a forward deployed sensor system or, in a specific embodiment, a forward deployed radar (FDR) system. The forward deployed sensor system includes a radar system and may also include other types of sensors such as optical sensors, acoustic sensors including sonar, and electromagnetic sensors. Further, the forward deployed sensor system may also include a communication system such as a full spectrum receiver/transmitter, a ship to ship relay transponder, a satellite communication system, and global positioning system (GPS) capability. The forward deployed sensor system is able to detect objects in the air, on the sea, and underwater, and communicate such detection to a ship, submarine, aircraft, satellite, or other remote location. Such systems may be used to augment the protection of shipping lanes by military or security forces to allow for peaceful commerce and utility of the sea by all nations.

Generally, the present disclosure relates to a forward deployed sensor system or, in a specific embodiment, a forward deployed radar (FDR) system. The forward deployed sensor system includes a radar system and may also include other types of sensors such as optical sensors, acoustic sensors including sonar, and electromagnetic sensors. Further, the forward deployed sensor system may also include a communication system such as a full spectrum receiver/transmitter, a ship to ship relay transponder, a satellite communication system, and global positioning system (GPS) capability. The forward deployed sensor system is able to detect objects in the air, on the sea, and underwater, and communicate such detection to a ship, submarine, aircraft, satellite, or other remote location. Such systems may be used to augment the protection of shipping lanes by military or security forces to allow for peaceful commerce and utility of the sea by all nations.

An attitude adjustment apparatus for a self-propelled bio-inspired robotic fish includes a fish body, where the fish body includes: a housing; a center-of-gravity adjustment assembly, located in the housing to adjust a center of gravity of the fish body, and including at least one counterweight and a screw-slider mechanism that drives the counterweight to move in a head-to-tail direction; and a suction and drainage system, located in the housing to adjust a weight of the fish body, and including a ballast tank and a water control assembly for controlling a water level in the ballast tank. The center-of-gravity adjustment assembly is combined with the suction and drainage system to rapidly change the weight and center of gravity of the fish body, so as to quickly adjust the pitching attitude and heaving state of the robotic fish.

An attitude adjustment apparatus for a self-propelled bio-inspired robotic fish includes a fish body, where the fish body includes: a housing; a center-of-gravity adjustment assembly, located in the housing to adjust a center of gravity of the fish body, and including at least one counterweight and a screw-slider mechanism that drives the counterweight to move in a head-to-tail direction; and a suction and drainage system, located in the housing to adjust a weight of the fish body, and including a ballast tank and a water control assembly for controlling a water level in the ballast tank. The center-of-gravity adjustment assembly is combined with the suction and drainage system to rapidly change the weight and center of gravity of the fish body, so as to quickly adjust the pitching attitude and heaving state of the robotic fish.

An underwater watercraft including a passenger compartment and an ingress/egress port in which the watercraft has buoyancy and center of gravity adjusted to maintain a generally level or other desired attitude when submerged, and an optionally angled attitude at a water surface for ingress/egress. The attitude is also adjustable via the placement of ballast and optionally including a movable ballast that adjusts the location of the center of gravity as desired. The ingress-egress port optionally includes an entry elevated from a main passenger compartment and including a riser and optionally removable or concealable handrails. The ingress-egress port has an angled orientation in a submerged mode, and an optional orientation generally parallel to the water surface or angled but above the surface in a surface mode.

An underwater watercraft including a passenger compartment and an ingress/egress port in which the watercraft has buoyancy and center of gravity adjusted to maintain a generally level or other desired attitude when submerged, and an optionally angled attitude at a water surface for ingress/egress. The attitude is also adjustable via the placement of ballast and optionally including a movable ballast that adjusts the location of the center of gravity as desired. The ingress-egress port optionally includes an entry elevated from a main passenger compartment and including a riser and optionally removable or concealable handrails. The ingress-egress port has an angled orientation in a submerged mode, and an optional orientation generally parallel to the water surface or angled but above the surface in a surface mode.

A fixed-wing aerial underwater vehicle includes a shell component, a flight component and a pneumatic buoyancy component. The flight component includes a fixed wing and rotors, and the fixed wing and the rotors are mounted in the shell component. The pneumatic buoyancy component includes an air bladder and an inflation and deflation portion, and the inflation and deflation portion can inflate and deflate the air bladder. The air bladder is installed on the shell component, a containing space is formed in the shell component, and the inflation and deflation portion is partially or entirely installed in the containing space. Each rotor includes a rotor supporting rod, a motor base, a motor and a propeller, which are sequentially connected. A control method for the fixed-wing aerial underwater vehicle mentioned above is further provided.