Disengaging actuator

[teemuv]

Hi everyone!

I was reading through the forum but didn't see anything about this. Sorry if it's been discussed already. It seems that most of the users of pypilot are using sailboats and it's easy to manually disengage the AP actuator. 

My situation is as follows:

I have a trawler boat that weighs about 2500kg and it currently has Raymarine wheelpilot that has gear drive that is broken in a way that when I put the AP on standby, the manual steering is so heavy that I need to really put my weight on the wheel to be able to steer the boat. This is a common issue with the Raymarine model and they sell updated replacement part for it but that costs over 800€ so not really interested in that. 

So my question is, how you have managed to disengage the actuator or what kind of system you have built if it's in a position that is not "easily accessible"? I would like to replace the Raymarine pilot with pypilot and add actuator directly to the tiller that is located in the back cabin. I can access this but it is not the best solution to jump from cockpit to the back cabin and unscrew the actuator every time I want to manually steer the boat. And my boat has cable steering. 

I could of course build some belt drive directly to the wheel but I would much rather go with the actuator, it's more reliable, quieter and keeps the cockpit clutter free when the steering gear is hidden in the back cabin.

[abarrow]

You are looking for an actuator with a clutch. The Raymarine actuator has one (I just had mine open last week).

No idea about third party actuators, but that's how you'd search for it anyway.

[teemuv]

Raymarine actuator is 900€

So that is out of the question. I was doing some further research and I might go with the following:
- Use 2-way joystick with relay to "manually" drive the boat (control the actuator) with the possibility to put Arduino + speed controller between the joystick and actuator to make the controlling more precise
- When AP is on, use pypilot to control the actuator

As a backup, I can leave the cable drive installed but just ditch the big wheel and use some smaller emergency wheel in it's place. If the actuator/electronics fails, I can disconnect the actuator from the rudder and use the wheel to steer the boat.

This setup will cost less than 100€, compared to that Raymarine

[seandepagnier]

Pretend whatever actuator you have does the worst possible thing (turns continuously in one direction and any clutch system you have will not disengage) It is essential that even in this situation you can quickly take over manual control.

I am trying to figure out clutch systems for wheel drives, but it is not simple. For example, my thought was to 3d print a large gear bolted to the wheel and have the motor with a smaller gear slide into place to engage. The issue here is mostly alignment, it is just almost impossible to get it close enough. Then belts come to mind, but this requires some sort of clutch. Most systems still have some amount of friction despite a clutch, which may be acceptable to the people selling them, in my mind it is not really good at all to make the boat more physical work to manually steer.

I am afraid there is no easy or perfect solution to this problem even if you paid a lot of money. I would start out getting something working that you can manually disconnect if needed.

[nousian]

You are looking for an actuator with a clutch. The Raymarine actuator has one (I just had mine open last week).

No idea about third party actuators, but that's how you'd search for it anyway.

The Raymarine in question is of mechanical type, with a ball screw and magnetic clutch?

I really prefer the hydraulic ones with solenoid clutch, whether with an integrated pumpmotor or external.

I dunno about cost, they might be marginally more expensive, but those are quite bullet proof, the solenoid clutch especially. Failure mode is typically such that you can always steer the boat manually, seals leaking hydraulic fluid and such, and usually happen gradually, not instantly, which is nice. You'll get drops of oil in your bilge weeks before the steering fails. I have lost a steering once hundreds of miles offshore, it was.... educational.

Most are manufactured by UK company Hypro, and sold under AP brands like Simrad. I believe even Ray sells one in their bigger sizes.