Out of the black sliced a strong, chill wind, blowing the Swan 46 downwind at seven knots. Bermuda was 200 miles ahead as Rhode Island quickly slipped more than 440 miles from the stern. Huddled behind the wheel, spray sounded like pebbles sprinkling the plastic of my foul weather hood pulled tightly over my head. Suddenly the companionway hatch flew open spilling light into the cockpit and hammered a pounding into my startled heart.
I had been so relaxed enjoying the ride – but now had to jump to the wheel.
The crewman plopped into the damp cockpit and asked how things were going. I made it look so easy to talk and casually hold a precise course. Actually the autopilot was moving me and I was cheating by using it. It was no longer my turn but I could not let the new watch take the helm and discover my secret. Fortunately we both agreed the jib needed a slight adjustment. With that opportunity I hit the standby button and slipped the sun cover over the controller.
I was the captain but I wanted everyone on board to be fully competent at hand steering and not be enticed by the autopilot. There would be plenty of time south of Bermuda to learn how to steer a boat to the Caribbean by merely pushing a few buttons. As on most passages, this boat would never steer a straighter course than when the rudder was under control of the autopilot. As a delivery captain I have used many Raymarine autopilots, and Raymarine is what my wife and I have chosen to steer our Valiant 40, Brick House, around the world.
THE SYSTEM
There are five main components to an autopilot: The course computer, controller, drive mechanism, fluxgate compass and the rudder position sensor.
CLICK TO VIEWRaymarine's S3G course computer (see photo) is the brain of the autopilot. The course computer receives its heading information from the remotely-mounted fluxgate compass. The fluxgate compass gives precise heading information despite the rocking and rolling of the vessel due to the Gyro (stabilization) technology used with the S3G computer system. The S3G also has what they call "AST," which is short for Advanced Steering Technology, with an "auto learn" ability. The unit actually gets to know the steering habits of your particular boat, and adjusts over time accordingly. In short, we chose the S3G because it is at the top in brainpower and can handle many functions when programmed to do so.
CLICK TO VIEWThe drive mechanism (see photo) is the muscle that moves the rudder. Initially I wanted a hydraulic drive as those units always worked flawlessly on the larger boats I delivered. However, Raymarine Pre-Sales support convinced us that a hydraulic unit in a remote area would not be user-repairable, probably not even technician repairable, and that it would involve shipping the part back to be repaired in a controlled environment.
The linear unit has parts that, by a savvy boat owner, could be swapped or repaired on board. We chose the Type 2 Long Linear Drive, for boats up to 44,000 pounds. Certainly oversized but everything on our boat is built to easily go the distance.
CLICK TO VIEWThe Controller (see photo) is the small box in the cockpit with buttons for controlling the direction of the boat. We chose the simplest controller with the least user options: the ST6002.
INSTALLATION
When I looked into the big void I had made by removing a propane locker at the back of the boat, I could not visualize in what direction the tiller arm would extend from the rudder shaft or where the linear drive would mount and how the two would meet and support themselves in mid air.
CLICK TO VIEWOur technician finally stepped aboard carrying a shiny bronze tiller arm (see photo). The tiller arm is a stubby, strong, bronze lever that bolts onto the rudderpost. I had previously measured the rudderpost with a dial caliper (see photo) and ordered the 10-inch arm our technician requested. Edson tiller arms are available in 10-inch and 15-inch lengths. Edson milled the collar of the tiller arm according to my measurements to fit exactly over the rudderpost, and they allow a .006-inch clamping action onto the rudderpost. This tight clamping to the rudderpost is necessary for optimum strength. If too tight, however, the clamp could bend. Too loose and the arm could work loose or drop.
