A couple of weeks ago I had the pleasure of meeting a fellow H37 Cutter owner (Rainer of Fred V) for a beer and some good boat talk. He was very interested in my wind vane self steering and I agreed to send him some pictures. Since I don’t know of any other H37Cs fitted with this, I thought I would do a little show n’ tell...
I installed a Cape Horn wind vane on Calypso about 8 years ago. I think it may be the best addition I have made to the boat. Why wind vane self steering instead of an Autohelm or other type of auto pilot? For one thing, it puts zero drain on the battery. When on a blue water passage in my boat (something that’s on my bucket list) the benefits are significant. Also, a wind vane does a better job of steering the boat under sail. Finally, such an installation can be less expensive. So, referring to the photos below, I will attempt to show how my wind vane self steering works for me.
My Cape Horn is what is called a servo- pendulum wind vane. This just means that a small force (the wind direction) is coupled to a large force (the motion of the boat through the water) to generate control of Calypso’s rudder.
Photo 1 shows the wind vane itself. It just flops from side to side (yellow arrows) depending on which side the wind hits. When it is pointing straight into the wind, it stands up straight. The whole wind vane is mounted on a turret that turns, allowing me to adjust the wind angle I want Calypso to sail to, i.e close hauled, beam reach, run etc.
The action of the wind vane is linked to the servo pendulum oar (Photo 2). It is a common misconception that this oar somehow ‘steers’ the boat as an auxilary rudder. Rather, the wind vane rotates the oar slightly on its axis (yellow arrow). This causes a change in the ‘attack angle’ of the oar in the water moving past the oar (as the boat is underway) causing the oar to swing to port or starboard, as indicated by the red arrows.
The port/starboard motion of the oar is a very large force that is transmitted via the tube that is mounted through the transom to a small quadrant located in the lazarette (Photo 3). The quadrant is attached to Calypso’s main steering system by a series of blocks and lines (Photo 4). I have tried to show the transmission of a wind vane steering force to the main steering system, using red arrows, in Photo 5. The forces go through three turning blocks, the last of which is attached to the Edson Radial Drive disk on Calypso’s rudder shaft. After this last block, the line’s bitter end is routed to a fixed point (designated by the broken red line I drew). The fixed point is, in fact a cleat at the back of the cockpit (Photo 6). The cleat acts as a sort of clutch; I can engage or disengage the wind vane self steering at will. Once engaged, the wind vane takes control and Calypso’s wheel turns back and forth as though under the hand of a ghostly helmsman.
The Cape Horn provides an added bonus: I can use a small and inexpensive ‘tiller pilot’, such as would be used on a small keel boat, to take the place of the wind vane input to the servo pendulum oar. With this setup I can use the Cape Horn to steer to a compass course (or for that matter, a GPS waypoint) while motoring (Photo7 ), giving me all the benefits of an Autohelm too. The tiller pilot doesn’t have to work hard at all, since the servo pendulum oar is providing all the force for steering (Photo 8) and the small amount of electricity used is insignificant, since the engine is running anyway. Calypso follows the set course (Photo 9) and I am free to attend to other tasks, such a reading a good sailing magazine (while always maintaining a proper lookout, of course!)
I installed a Cape Horn wind vane on Calypso about 8 years ago. I think it may be the best addition I have made to the boat. Why wind vane self steering instead of an Autohelm or other type of auto pilot? For one thing, it puts zero drain on the battery. When on a blue water passage in my boat (something that’s on my bucket list) the benefits are significant. Also, a wind vane does a better job of steering the boat under sail. Finally, such an installation can be less expensive. So, referring to the photos below, I will attempt to show how my wind vane self steering works for me.
My Cape Horn is what is called a servo- pendulum wind vane. This just means that a small force (the wind direction) is coupled to a large force (the motion of the boat through the water) to generate control of Calypso’s rudder.
Photo 1 shows the wind vane itself. It just flops from side to side (yellow arrows) depending on which side the wind hits. When it is pointing straight into the wind, it stands up straight. The whole wind vane is mounted on a turret that turns, allowing me to adjust the wind angle I want Calypso to sail to, i.e close hauled, beam reach, run etc.
The action of the wind vane is linked to the servo pendulum oar (Photo 2). It is a common misconception that this oar somehow ‘steers’ the boat as an auxilary rudder. Rather, the wind vane rotates the oar slightly on its axis (yellow arrow). This causes a change in the ‘attack angle’ of the oar in the water moving past the oar (as the boat is underway) causing the oar to swing to port or starboard, as indicated by the red arrows.
The port/starboard motion of the oar is a very large force that is transmitted via the tube that is mounted through the transom to a small quadrant located in the lazarette (Photo 3). The quadrant is attached to Calypso’s main steering system by a series of blocks and lines (Photo 4). I have tried to show the transmission of a wind vane steering force to the main steering system, using red arrows, in Photo 5. The forces go through three turning blocks, the last of which is attached to the Edson Radial Drive disk on Calypso’s rudder shaft. After this last block, the line’s bitter end is routed to a fixed point (designated by the broken red line I drew). The fixed point is, in fact a cleat at the back of the cockpit (Photo 6). The cleat acts as a sort of clutch; I can engage or disengage the wind vane self steering at will. Once engaged, the wind vane takes control and Calypso’s wheel turns back and forth as though under the hand of a ghostly helmsman.
The Cape Horn provides an added bonus: I can use a small and inexpensive ‘tiller pilot’, such as would be used on a small keel boat, to take the place of the wind vane input to the servo pendulum oar. With this setup I can use the Cape Horn to steer to a compass course (or for that matter, a GPS waypoint) while motoring (Photo7 ), giving me all the benefits of an Autohelm too. The tiller pilot doesn’t have to work hard at all, since the servo pendulum oar is providing all the force for steering (Photo 8) and the small amount of electricity used is insignificant, since the engine is running anyway. Calypso follows the set course (Photo 9) and I am free to attend to other tasks, such a reading a good sailing magazine (while always maintaining a proper lookout, of course!)
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