Disclosed are a method and a virtual sensor system for determining the speed through water of a marine vessel. The method includes obtaining propeller revolutions per minute and at least one of torque at propeller, propulsion power, thrust and engine fuel flow, obtaining speed over ground or logged data from one or more speed through water logs of the vessel and using the obtained data and hydrodynamic modelling to determine the speed through water of the vessel.

Disclosed are a method and a virtual sensor system for determining the speed through water of a marine vessel. The method includes obtaining propeller revolutions per minute and at least one of torque at propeller, propulsion power, thrust and engine fuel flow, obtaining speed over ground or logged data from one or more speed through water logs of the vessel and using the obtained data and hydrodynamic modelling to determine the speed through water of the vessel.

Provided are a ship and a power management method of the ship. The ship comprises: a power grid; at least one generator that is connected to the power grid and supplies electricity to the power grid; a high-capacity battery connected to the power grid, and charged by receiving the electricity from the power grid or discharged to supply power to the power grid; a plurality of load components connected to the power grid; and a controller for receiving generator load information from the at least one generator, sensing a voltage of the power grid to calculate a current load and an average load, and controlling the generator to bear the average load and the high-capacity battery to bear a difference load between the current load and the average load.

Provided are a ship and a power management method of the ship. The ship comprises: a power grid; at least one generator that is connected to the power grid and supplies electricity to the power grid; a high-capacity battery connected to the power grid, and charged by receiving the electricity from the power grid or discharged to supply power to the power grid; a plurality of load components connected to the power grid; and a controller for receiving generator load information from the at least one generator, sensing a voltage of the power grid to calculate a current load and an average load, and controlling the generator to bear the average load and the high-capacity battery to bear a difference load between the current load and the average load.

A computer-implemented method of tracking vessel movement which comprises receiving a first vessel data message comprising a first vessel identifier, the first vessel data message having been transmitted at a first time and being associated with a first position; and receiving a second vessel data message comprising a second vessel identifier, the second vessel data message having been transmitted at a second time and being associated with a second position. The method also comprises determining if the first vessel identifier and the second vessel identifier are related. If the first vessel identifier and the second vessel identifier are related, a speed required for a vessel to have moved from the first position to the second position is determined; which is then determined if the speed is below a speed threshold; and if the speed is below the speed threshold, the first position is associated with the second position.

A computer-implemented method of tracking vessel movement which comprises receiving a first vessel data message comprising a first vessel identifier, the first vessel data message having been transmitted at a first time and being associated with a first position; and receiving a second vessel data message comprising a second vessel identifier, the second vessel data message having been transmitted at a second time and being associated with a second position. The method also comprises determining if the first vessel identifier and the second vessel identifier are related. If the first vessel identifier and the second vessel identifier are related, a speed required for a vessel to have moved from the first position to the second position is determined; which is then determined if the speed is below a speed threshold; and if the speed is below the speed threshold, the first position is associated with the second position.

A system for detecting threats using an overt threat detector, the system includes a computer-readable memory configured to store computer executable instructions; a processor configured to execute the computer executable instructions, the computer executable instructions comprising receiving historical data regarding vessel patterns in a geographic area; generating, using a computer processor, at least one overt threat model based on the received historical data; receiving tracking data of vessels currently in the geographic area; analyzing, using the computer processor, the tracking data of vessels using the at least one overt threat model; and modifying, using the computer processor, the tracking data of vessels based on the results of the analyzing step; and an output device configured to output the modified tracking data of vessels is disclosed.

According to an example aspect of the present invention, there is provided a marine propulsion system (1) comprising a first portion (4) and a second portion (5) of a set of movable foils, a movement mechanism (2) coupled to the first portion (4) and the second portion (5) of the set of movable foils and configured to simultaneously control a motion of the first portion (4) and the second portion (5) of the set of foils along a closed first trajectory (6) comprising a first direction (17) and a second direction (18) which is different than the first direction (17), and a pitch mechanism (3) coupled to the first portion (4) and the second portion (5) of the set of movable foils and configured to control a pitch angle () of the first portion (4) and the second portion (5) of the set of movable foils, and wherein the pitch angle () of at least a part of the second portion (5) of the set of foils is dependent on an incoming fluid flow (v.sub.x), the motion of the second portion (5) of the set of foils, and a flow (v.sub.ind) induced by at least a part of the first portion (4) of the set of foils.

According to an example aspect of the present invention, there is provided a marine propulsion system (1) comprising a first portion (4) and a second portion (5) of a set of movable foils, a movement mechanism (2) coupled to the first portion (4) and the second portion (5) of the set of movable foils and configured to simultaneously control a motion of the first portion (4) and the second portion (5) of the set of foils along a closed first trajectory (6) comprising a first direction (17) and a second direction (18) which is different than the first direction (17), and a pitch mechanism (3) coupled to the first portion (4) and the second portion (5) of the set of movable foils and configured to control a pitch angle () of the first portion (4) and the second portion (5) of the set of movable foils, and wherein the pitch angle () of at least a part of the second portion (5) of the set of foils is dependent on an incoming fluid flow (v.sub.x), the motion of the second portion (5) of the set of foils, and a flow (v.sub.ind) induced by at least a part of the first portion (4) of the set of foils.

This disclosure provides improved nautical craft that can travel and navigate on their own. A hybrid vessel is described that converts wave motion to locomotive thrust by mechanical means, and also converts wave motion to electrical power for storage in a battery. The electrical power can then be tapped to provide locomotive power during periods where wave motion is inadequate and during deployment. The electrical power can also be tapped to even out the undulating thrust that is created when locomotion of the vessel is powered by wave motion alone.