What kind of autopilot is this?

[Bigjim]

I bought a 1978 Columbia 10.7 in December and I'm slowly getting her back in shape. One of the projects I'm working on is figuring out what kind of autopilot I can use with the boat.

While climbing down in the port lazarette I found the following steering system already installed. There are no labels, logos or brand names on the boxes.

Can anyone tell me what kind of system this is?

[captd44]

Looks like a old Benmar drive unit. They last forever.

[Bigjim]

I contacted the Benmar company and they agreed. I'm trying to get more info, but after a couple of emails, he stopped replying. I'm trying to find out if the autopilot interfaces with the Garmin chart plotter that came with the boat. All the wiring looks so old that I don't think it works any more.

[smac999]

that looks just like a motor / drive unit. you still need a whole autopilot system with display. maybe it's there or not.

you could probably buy a new system and use that drive.

[rgleason]

I believe pypilot would drive that unit. Pypilot is based on a raspberry pi, and designed and programmed by sean depagnier. Google it. Perhaps it still has a controller that works? If not sean's controller can probably help there too.

[Bigjim]

Originally Posted by rgleason

I believe pypilot would drive that unit. Pypilot is based on a raspberry pi, and designed and programmed by sean depagnier. Google it. Perhaps it still has a controller that works? If not sean's controller can probably help there too.

Last year I built a plotter using a Raspberry PI. Perhaps I can adapt that one

[Frankly]

As you have already figured out this is a Benmar Power unit. Maybe one of the best rudder drive units ever manufactured. The unit on the side is probably some type of electric drive for the clutch. Pull the back cover off and you will find a printed circuit card with the motor plugged into it. Un connect the motor and apply 12V directly to the motor leads. Should drive in both directions (reverse the polarity). Keep your fingers out of the way.

I have been running one for a number of years and driving it with an assortment of Raymarine AP units (currently using an X-5 /6002. Just connect the AP motor output drive and toss the Benmar electrics. Mine is set up with a simple mechanical clutching arrangement. If it is functioning OK then pull the unit and clean and relube the gears (metal gears and oillite bearings). open the motor, blow out the dust, and ad a little warm oil to the motor ball bearings.

If you can't get it to work I have 3 spares. I spent 30 years designing automatic control systems for the US Navy. IMO there is not a better solution to a rack and pinion rudder drive unit

[Bigjim]

Originally Posted by Frankly

As you have already figured out this is a Benmar Power unit. Maybe one of the best rudder drive units ever manufactured. The unit on the side is probably some type of electric drive for the clutch. Pull the back cover off and you will find a printed circuit card with the motor plugged into it. Un connect the motor and apply 12V directly to the motor leads. Should drive in both directions (reverse the polarity). Keep your fingers out of the way.

I have been running one for a number of years and driving it with an assortment of Raymarine AP units (currently using an X-5 /6002. Just connect the AP motor output drive and toss the Benmar electrics. Mine is set up with a simple mechanical clutching arrangement. If it is functioning OK then pull the unit and clean and relube the gears (metal gears and oillite bearings). open the motor, blow out the dust, and ad a little warm oil to the motor ball bearings.

If you can't get it to work I have 3 spares. I spent 30 years designing automatic control systems for the US Navy. IMO there is not a better solution to a rack and pinion rudder drive unit

I will try those things when I get a spare moment. Do you have schematics or diagrams for the systems you set up?

[deblen]

Your rudder is like mine.
It has a built in rope/trash catcher at the top leading edge.
This is my solution-works well for me. / Len



https://www.dropbox.com/s/g4zvkf5fvq...0stop.JPG?dl=0

[Frankly]

Originally Posted by Bigjim

I will try those things when I get a spare moment. Do you have schematics or diagrams for the systems you set up?

Not much diagram to the drive end. Whatever AP System you choose will have two motor connections. Just connect the two Benmar motor leads to these terminals. Could use a new Evo (just sell the wheel drive on ebay), or buy an X-5 off ebay or probably half a dozen other models. The Benmar drive unit has a mechanical slip clutch to protect against two blocking something. In windy conditions with bad sail trim I have managed to slip this clutch on a couple of occasions. This will happen below the max drive current of the recent Raymarine wheelpilot systems. If you decide to stick with the electric engage clutch, then will need to provide a switched source of 12V. Could be a simple toggle switch, or some AP systems provide this when you punch the auto button.

All autopilots will work better (less hunting, tighter heading control) with a rudder position sensor connected to the system.

Oh, and check the motor direction. When the bow is off to the Stbd rudder should correct this not make it worse. If the drive direction is not correct just reverse the motor connections.


Good luck.