Understanding Carina’s lifting keel system
Carina of Solent is equipped with a lifting keel, a feature that enhances her performance and versatility. However, the details of the system are currently spread between several documents, and the interaction and location of the various switches, fuses, and controls can be confusing. The diagrams and the annotated photograph of the hydraulics bay show the various switches, controls, sensors, and displays that make it all work and let the helmsman know the keel status. This blog aims to simplify things by pulling everything into one place.
How the system works
Start at the battery control panel in the aft cabin wardrobe. You will find a switch marked ‘Thrust/Keel/Windlass’, which applies 12 volts to all three systems. Power flows through a 325A fuse into a large-diameter cable that runs the length of the boat. If you touch this cable, even the uninsulated connections, it won’t do you any harm. If you need to carry out any maintenance near this circuit, make sure it is switched off at the battery control panel. If you don’t, it is likely to give you a big surprise and will blow the fuse.
The next step in the circuit is the 80A circuit breaker {H} which protects the hydraulic motor when the keel switch is selected UP to operate the solenoid {L} that applies power to it. Note the signal from the keel switch is +12V via a 7.5A inline fuse {J}. The increased hydraulic pressure drives the Keel Lift Piston. The piston is connected to the keel pennant, the large Dyneema rope, that lifts the rear edge of the keel.
Keel down, position sensing and manual override
To lower the keel, select the DOWN position. This releases pressure from the piston via valve (D). Next to the piston is a fuel/water tank sensor, with a float connected to the piston. The Keel Position Sensor contains a series of resistors whose value depends on the position of float.
The value of this resistance (0 to 190 ohms) is converted to a digital value which illuminates the 8 light emitting diodes on the control panel. The power for this LED display can be switched off at the 12V Distribution Panel / Auxiliary Equipment / (Keel Ind) in the saloon when the vessel is used at night.
In the event of electrical failure, check the switches, fuses, and circuit breakers first. If that doesn’t solve the problem, the keel can be raised using the manual pump {B}. The handle for this pump is mounted inside the cupboard under the Nav Table seat. The keel is lowered by operating the release valve {A}.
Have a question about Carina’s keel or need help troubleshooting onboard? Get in touch or refer to the onboard manuals before your next trip.