The control method of a ship is used for the ship. The ship is equipped with a plurality of power sources including a first power source and a second power source, and has a plurality of propulsion modes in which a power source used for propulsion of a hull is different between the plurality of power sources. The control method of the ship includes adjusting an output value related to a propulsive force of a hull to a value corresponding to an operation amount of an operation acceptor and changing a correspondence relation between the operation amount and the output value in accordance with a propulsion mode.

A leash system and methods of use are provided that includes a leash cord configured to be affixed at a first end portion to a user of a personal watercraft, a switch cord, and an anchoring cord. The switch cord has a first end portion affixed to a key for connection to a kill switch of the watercraft and a second end portion affixed to the leash cord. The anchoring cord has a first end portion configured to fixedly secure the anchoring cord to the watercraft and a second end portion affixed to the leash cord. A loop is affixed in preferred examples along the anchoring cord that is configured to slidably receive the switch cord therethrough. When the leash cord is pulled taut while the anchoring cord is fixedly secured to the watercraft, the first end portion of the switch cord is drawn toward the loop to remove the key from the kill switch.

A method of controlling an electric marine propulsion system to propel a marine vessel includes receiving a user-set time, determining a time remaining based on the user-set time, and identifying a battery charge level of a power storage system on the marine vessel. A required battery power is then determined based on the time remaining and the battery charge level, and then an output limit is determined based on the required battery power to enable propelling the marine vessel for the user-set time without recharging the power storage system. The propulsion system is automatically controlled so as not to exceed the output limit.

A method of controlling an electric marine propulsion system to propel a marine vessel includes receiving a user-set time, determining a time remaining based on the user-set time, and identifying a battery charge level of a power storage system on the marine vessel. A required battery power is then determined based on the time remaining and the battery charge level, and then an output limit is determined based on the required battery power to enable propelling the marine vessel for the user-set time without recharging the power storage system. The propulsion system is automatically controlled so as not to exceed the output limit.

A method of controlling an electric marine propulsion system configured to propel a marine vessel includes receiving a user-set distance, identifying a battery charge level of a power storage system on a marine vessel and identifying an energy utilization value. An output limit is then determined based on a remaining distance, the battery charge level, and the energy utilization value. The propulsion system is then automatically controlled so as to not exceed the output limit, enabling the marine vessel to travel the user-set distance without recharging the power storage system.

A method of controlling an electric marine propulsion system configured to propel a marine vessel includes receiving a user-set distance, identifying a battery charge level of a power storage system on a marine vessel and identifying an energy utilization value. An output limit is then determined based on a remaining distance, the battery charge level, and the energy utilization value. The propulsion system is then automatically controlled so as to not exceed the output limit, enabling the marine vessel to travel the user-set distance without recharging the power storage system.

A propulsion system includes a cylindrical shaft member coupled to a motor with a motor frame; said shaft member mechanically coupled to a disc members with radius, to rotate in a dynamically and statically balanced state with said shaft when said motor rotates; the apparatus further comprising a power source to supply power to said motor to rotate said shaft member with said disc members; each said disc members comprising an annular radial array of material segments extending radially to the radius; said material segments comprising of a material that responds to electromagnetic fields to change shape radially on said disc member; such that when power is supplied to rotate the motor, the motor rotates the disc members and when each such material segment rotates to an angular location of the shaft member relative to a fixed point on the motor frame, each said material segment is supplied with said electromagnetic field; and said material responds to said electromagnetic field to change its shape radially to a new radius different from, at said angular location, and such that the mass of said material segment is redistributed radially at the radius R2 in said material segment in said angular location; and such that the difference in centripetal forces acting on said change in radial location from R1 to R2 at said angular location creates a radial force on said shaft member in the direction of the said angular location.

A propulsion system includes a cylindrical shaft member coupled to a motor with a motor frame; said shaft member mechanically coupled to a disc members with radius, to rotate in a dynamically and statically balanced state with said shaft when said motor rotates; the apparatus further comprising a power source to supply power to said motor to rotate said shaft member with said disc members; each said disc members comprising an annular radial array of material segments extending radially to the radius; said material segments comprising of a material that responds to electromagnetic fields to change shape radially on said disc member; such that when power is supplied to rotate the motor, the motor rotates the disc members and when each such material segment rotates to an angular location of the shaft member relative to a fixed point on the motor frame, each said material segment is supplied with said electromagnetic field; and said material responds to said electromagnetic field to change its shape radially to a new radius different from, at said angular location, and such that the mass of said material segment is redistributed radially at the radius R2 in said material segment in said angular location; and such that the difference in centripetal forces acting on said change in radial location from R1 to R2 at said angular location creates a radial force on said shaft member in the direction of the said angular location.

System and methods are provided that relate to a drive arrangement for propelling a boat, in particular a kayak. In some embodiments, the drive arrangement can include an electric drive motor with a shaft and a receiving device for receiving the shaft. An arresting element can be provided for determining a first desired distance along the shaft between the receiving device and the drive motor.

System and methods are provided that relate to a drive arrangement for propelling a boat, in particular a kayak. In some embodiments, the drive arrangement can include an electric drive motor with a shaft and a receiving device for receiving the shaft. An arresting element can be provided for determining a first desired distance along the shaft between the receiving device and the drive motor.