Braking System for Gyroscopic Boat Roll Stabilizer

1 . A gyroscopic boat roll stabilizer configured to be installed in a boat, comprising:

a gimbal assembly including a support frame and enclosure configured to rotate about a gimbal axis;

a flywheel assembly rotatably mounted inside the enclosure for generating a torque that is applied to counter a rolling motion of the boat;

a braking system for controlling precession of the flywheel assembly, the braking system comprising:

a first hydraulic actuator connected between the support frame and the enclosure and configured to resist precession of the flywheel assembly about the gimbal axis;

a main valve controlling hydraulic fluid flow in a fluid flow path to the first actuator;

a heat exchanger to dissipate heat generated by fluid flow through the main valve.

2 . The gyroscopic boat roll stabilizer of claim 1 , wherein heat exchanger comprises a block having cooling passages therein to carry coolant to dissipate heat generated by fluid flow through the main valve.

3 . The gyroscopic boat roll stabilizer of claim 2 , wherein the main valve forms a portion of a manifold assembly; and wherein the manifold assembly comprises the block having the cooling passages.

4 . The gyroscopic boat roll stabilizer of claim 1 :

wherein the first actuator is configured to resist precession of the flywheel assembly about the gimbal axis in a first direction;

further comprising a second hydraulic actuator connected between the support frame and the enclosure and configured to resist precession of the flywheel assembly about the gimbal axis in a second direction;

wherein the first and second actuators are configured to enable precession of the flywheel assembly about the gimbal axis in both the first and second directions;

wherein the fluid flow path fluidically connects the first and second actuators.

5 . The gyroscopic boat roll stabilizer of claim 5 , wherein the main valve has first and second inputs and first and second outputs; wherein the main valve is connected to the first and second actuators by respective fluid lines that allow fluid flow between the main valve and the corresponding actuator.

6 . The gyroscopic boat roll stabilizer claim 4 :

wherein the first actuator comprises a first fluid cylinder;

wherein the second actuator comprises a second fluid cylinder;

further comprising a first bypass line providing a fluid low path between first and second ends of the first fluid cylinder that bypasses the main valve;

further comprising a second bypass line providing a fluid low path between first and second ends of the second fluid cylinder that bypasses the main valve.

7 . The gyroscopic boat roll stabilizer of claim 6 , wherein the first bypass line allows bidirectional flow between first and second ends of the first cylinder; and wherein the second bypass line allows bidirectional flow between first and second ends of the second cylinder.