Thruster apparatuses, and methods of operating same

1. A thruster apparatus comprising:

a thruster tunnel defining a thruster channel extending between opposite open ends of the thruster channel;

first and second propellers in the thruster channel between the opposite open ends of the thruster channel;

a first motor configured to rotate the first propeller;

a second motor configured to rotate the second propeller;

wherein the first and second motors are positioned in the thruster channel, wherein:

the first motor is a first hydraulic motor configured to rotate the first propeller in response to pressure of a first flow of pressurized hydraulic fluid; and

the second motor is a second hydraulic motor configured to rotate the second propeller in response to pressure of a second flow of pressurized hydraulic fluid separate from the first flow of pressurized hydraulic fluid.

2. The thruster apparatus of claim 1 , further comprising a first fluid conduit configured to receive a first common source of pressurized hydraulic fluid and to separate the first common source of pressurized hydraulic fluid into the first flow of pressurized hydraulic fluid and the second flow of pressurized hydraulic fluid.

3. The thruster apparatus of claim 2 , wherein:

the first hydraulic motor is configured to rotate the first propeller in a first rotation direction in response to flow of the first common source of pressurized hydraulic fluid in first flow direction; and

the second hydraulic motor is configured to rotate the second propeller in a second rotation direction opposite the first rotation direction in response to flow of the first common source of pressurized hydraulic fluid in the first flow direction.

4. A thruster apparatus comprising:

first and second propellers;

a first hydraulic motor configured to rotate the first propeller in response to pressure of a first flow of pressurized hydraulic fluid;

a second hydraulic motor configured to rotate the second propeller in response to pressure of a second flow of pressurized hydraulic fluid separate from the first flow of pressurized hydraulic fluid;

a first fluid conduit configured to receive a first common source of pressurized hydraulic fluid and to separate the first common source of pressurized hydraulic fluid into the first flow of pressurized hydraulic fluid and the second flow of pressurized hydraulic fluid, wherein the first hydraulic motor is configured to rotate the first propeller in a first rotation direction in response to flow of the first common source of pressurized hydraulic fluid in a first flow direction, and wherein the second hydraulic motor is configured to rotate the second propeller in a second rotation direction opposite the first rotation direction in response to flow of the first common source of pressurized hydraulic fluid in the first flow direction; and

a second fluid conduit configured to receive a second common source of pressurized hydraulic fluid and to separate the second common source of pressurized hydraulic fluid into a third flow of pressurized hydraulic fluid and a fourth flow of pressurized hydraulic fluid, wherein the first hydraulic motor is configured to rotate the first propeller in the second rotation direction in response to pressure of the third flow of pressurized hydraulic fluid when the second common source of pressurized hydraulic fluid flows in a second flow direction, and wherein the second hydraulic motor is configured to rotate the second propeller in the first rotation direction in response to pressure of the fourth flow of pressurized hydraulic fluid when the second common source of pressurized hydraulic fluid flows in the second flow direction.

5. The thruster apparatus of claim 1 , wherein the first hydraulic motor comprises a first gerotor.

6. The thruster apparatus of claim 5 , wherein the second hydraulic motor comprises a second gerotor.

7. The thruster apparatus of claim 1 , further comprising:

a first drive shaft coupling the first hydraulic motor to the first propeller; and

a second drive shaft coupling the second hydraulic motor to the second propeller.

8. The thruster apparatus of claim 1 , wherein: the first hydraulic motor is configured to rotate the first propeller independently of any gears between the first hydraulic motor and the first propeller, and the second hydraulic motor is configured to rotate the second propeller independently of any gears between the second hydraulic motor and the second propeller.

9. The thruster apparatus of claim 1 , wherein the thruster channel extends transversely through a hull of a ship.

10. The thruster apparatus of claim 9 , wherein the first and second hydraulic motors are positioned in the thruster channel between the first and second propellers.

11. The thruster apparatus of claim 1 , wherein the first and second hydraulic motors are positioned in the thruster channel between the first and second propellers.

12. The thruster apparatus of claim 1 , further comprising a thruster body in the thruster channel, wherein fluid conduits in the thruster body are configured to separate the first common source of pressurized hydraulic fluid into the first flow of pressurized hydraulic fluid and the second flow of pressurized hydraulic fluid.

13. The thruster apparatus of claim 12 , wherein the thruster channel extends transversely through a hull of a ship.

14. The thruster apparatus of claim 12 , wherein the fluid conduits in the thruster body are configured to separate the first common source of pressurized hydraulic fluid into the first flow of pressurized hydraulic fluid and the second flow of pressurized hydraulic fluid at a location between the first and second hydraulic motors.

15. The thruster apparatus of claim 1 , wherein:

the first hydraulic motor is configured to receive the first flow of pressurized hydraulic fluid from the first common source of pressurized hydraulic fluid independently of any controller, between the first fluid conduit and the first hydraulic motor, of flow of the first common source of pressurized hydraulic fluid to the first hydraulic motor; and

the second hydraulic motor is configured to receive the second flow of pressurized hydraulic fluid from the first common source of pressurized hydraulic fluid independently of any controller, between the first fluid conduit and the second hydraulic motor, of flow of the first common source of pressurized hydraulic fluid to the second hydraulic motor.

16. The thruster apparatus of claim 1 , wherein:

only a fluid conduit between the first fluid conduit and the first hydraulic motor is configured to control flow of the first flow of pressurized hydraulic fluid from the first common source of pressurized hydraulic fluid to the first hydraulic motor; and

only a fluid conduit between the first fluid conduit and the second hydraulic motor is configured to control flow of the second flow of pressurized hydraulic fluid from the first common source of pressurized hydraulic fluid to the second hydraulic motor.

17. The thruster apparatus of claim 2 , further comprising:

a second fluid conduit configured to receive a second common source of pressurized hydraulic fluid and to separate the second common source of pressurized hydraulic fluid into a third flow of pressurized hydraulic fluid and a fourth flow of pressurized hydraulic fluid,

wherein the first hydraulic motor is configured to, in response to pressure of the third flow of pressurized hydraulic fluid separated from the second common source of pressurized hydraulic fluid, rotate the first propeller in an opposite direction than in response to pressure of the first flow of pressurized hydraulic fluid separated from the first common source of pressurized hydraulic fluid, and

wherein the second hydraulic motor is configured to, in response to pressure of the fourth flow of pressurized hydraulic fluid separated from the second common source of pressurized hydraulic fluid, rotate the second propeller in an opposite direction than in response to pressure of the second flow of pressurized hydraulic fluid separated from the first common source of pressurized hydraulic fluid.

18. The thruster apparatus of claim 4 , further comprising a thruster tunnel defining a thruster channel extending between opposite open ends of the thruster channel, wherein the first and second propellers in the thruster channel between the opposite open ends of the thruster channel.