Models and evolution
My Alberg 30 Jean-du-Sud has a lovely classic transom, and to make the gear that would make it steer itself as discrete as possible, I hid some of it the lazarette. A horizontal tube passes through the transom, its forward end supported by a pair of struts; inside it, another smaller tube links the servo-pendulum trailing outside to a control arm inside, with lines to the boat’s steering gear. A vertical tube links the servo-pendulum to a vane in clear air above. I could not make it more discrete, or more solid, the gear being as strong as the stern of the boat.
I called it the Jean-du-Sud model.
I increased the scantlings to steer boats 40′ and above; Spray model.
The self-steering gear is integrated into the boat; part of it is inside, with lines led internally through blocks on the boat’s steering system, then jamming cleats in the cockpit. It also integrates electric autopilot steering when you replace the vane with a small tiller pilot to drive the servo-pendulum. The energy needed to move the rudder still coming from the servo-pendulum, the autopilot feeds on mere milli-amps and is never overworked.
Each gear is custom-built: the length of the horizontal axle varies on each boat to locate our control arm or quadrant in the most favourable position inside, regardless of the shape of the stern, whether it is classic, reverse or canoe. Height of the windvane tower is measured to locate the vane in clear air above a bimini; wetted area of the servo-pendulum is proportional to the rudder of the boat.
I was asked to make the last Contessa 26 built by JJ Taylor, steer itself. I could not use an integrated installation on a boat with an outboard rudder, so I shortened the horizontal axle to the minimum. It became the Varuna model.
Then Joshua, same configuration, but with the scantlings of the Spray. Those two models are totally outboard and steer the boat when an integrated installation is impossible.
When I was asked to make my first boat with a scoop stern steer itself, I figured I could use the Varuna configuration, but without mounting arms and with the horizontal axle directly on the scoop, long enough to locate the windvane tower at its forward end, against the transom.
Early on, I figured there was no reason a gear should be smack on the centre line. On Nicholson 31 Chance Encounter , we offset the horizontal axle to allow the outboard rudder to pivot. Performance was in no way affected.
Kim and Charlie Arcon honeymooned on Toucana, their Westsail 32, but Charlie was not happy with the Varuna I offered; he wanted a gear that could remain under the boomkin. I turned it around, replaced the control arm with a quadrant. Toucana model.
Annapolis 44 Jade had a long overhang with very raked transom and no room inside the lazarette for a control arm. We agreed that the mounting tube would not pass through the transom; we cut it to the same angle and welded it to a plate bolted to the transom, the quadrant replaced with an arm extending above the servo-pendulum, like on the Varuna. Jade model.
Moody 42 Tristaina from Ibiza had a step stern with davits. So we located the windvane tower at the forward end of the horizontal axle, in front of the CapeHorn quadrant and made it pass through the stern deck. Tristaina model.
With his wife and two teen-age daughters as crew, Rolland Trowbridge wanted to sail Precipice, a 32’ gaff-rigged cutter he had built himself, through the North-West passage. He needed a compact, sturdy integrated installation, but there was no space inside for the CapeHorn control arm. Instead, we welded eyes on the tube supporting the servo-pendulum for our control lines and led them to blocks on the back of the rudder head.
This became our Precipice model.
This was in 2010; since then, I did not have to come up with a new model, even though I sometimes combine features of different models to adapt to a stern configuration or steering system.
I expect the next challenge, convinced I will find the most elegant way to make any boat steer itself.
