(2024-02-02, 06:52 PM)MacKludger Wrote: Is your tiller really offset from your rudder post that much? I've never seen that on a sailboat before. Do you have any photos? Maybe I'm misunderstanding your diagram.
The standard stroke for tiller actuators is ~12" (300mm) at a distance of 18" up the tiller arm, so to have your actuator work as a linkage like you depict here, it seems like it would have to be a very large offset to allow the actuator to be at the midpoint when centered and have room to extend and retract when in operation. Beyond that, by leaving the actuator connected to your steering system all the time, I would be concerned that the constant push/pull on the actuator arm when hand steering in big seas would wear out your bearings very quickly. Finally, those actuator speeds seem on the slow side unless they are very powerful and very close to the rudder post. My tiller actuator is 45mm/sec and 300N by comparison, attached at the 18" distance from pivot on my tiller.
For my money, I'd go with one of the $80 actuators from ebay/aliexpress and build a waterproofing shell around it for placement in the cockpit. Less engineering and fewer points of failure that could affect your baseline ability to steer.
Thanks for responding.
Actually, the boat has dual rudders with a cross-link. I just simplified the schematic for illustration. So, there is plenty of room for any of those actuators to go from centerline to the cross link. It's been a while since I've been under there, but I believe the arms are around 8". I'll have to check. But the 1000N at 14 mm/sec version would almost be equivalent to your numbers. I'll need to check the arm sweep, but my gut feel is I won't even need the full 12" version. Also, the rudders are balanced and be fine tuned to require zero load, though I put a little just for rudder feel.
Another savings grace is this is a small boat and won't ever be out in big seas. Likely it'll only be in lakes, ICW, bays, and an occasional costal sailing.
BUT... your comment of the constant wear and tear just acting as a pushrod is an important consideration. I'll need to dig up what these things look like. I assumed a simple threaded rod with big honk'n nut making the connection... pushing the piston in/out.
Thanks.