Course Setter 21 Auto Pilot

I have a Course Setter 21 auto pilot by Benmar. Thanks to Sam here on the forum I now have an electronic set of manuals.

When I opened the enclosure I found the compass cylinder is filled with a fluid. I think the fluid is suppose to be there but I'm not 100% sure. The manual doesn't say anything about it but it does say that is should be mounted level. So I think the compass needs to float like a regular compass.

I have a theory on how the compass may be providing electronic signals to the auto pilot circuitry but before I dig any further I'm hoping someone can shed some light on this.

Anyone have experience with this model?

There is a little bit more to this story. If you want to read it go to page 9, post 166 of this thread. http://www.trawlerforum.com/forums/s34/prairie-36-improvements-25815-9.html#post658980

Bringing this to the surface. Hoping to get a reply from someone with experience on these systems. Thanks.

You might want to contact Benmar Marine. They still provide service to their autopilots.

Benmar Marine

The fluid dampa the oscillations of the compass card. years ago I refilled mine, i think it was similar. with clear mineral spirits.

FWIW I’ve had two boats with this exact autopilot, despite being old they are rock solid reliable. Current boat course setter was dead when I bought it, Benmar repaired it for a very reasonable price.

I think these are 70’s vintage but don’t know for sure.

I had a courseSetter 21R many boats (and many more years) ago, and ended up rebuilding it myself. As I recall, there are a series (I vaguely recall that there were 60 of them, 6 degrees apart; there may have been more, but the resolution wasn't great) of contacts around the perimeter of a compass. As the compass swings different contacts become active, allowing the "brain" to infer how far the boat had swung off course, and to then adjust accordingly. Pretty basic, but it sure beat hand steering (and made me REALLY appreciate Simrad's modern technology; actually, my happiness from going from hand steering to the CourseSetter was greater than my happiness from going from CourseSetter to really modern -- in terms of sheer course holding functionality, and disregarding all the extra features modern microprocessor based AP's offer, the CourseSetter was at least 90% as good as modern).

Anyway, the problem with my 21R was just that the contacts had become a little dirty. I polished them up and it was good as new. And from what I recall, there was no fluid in mine. I later learned that Benmar would rebuild for a couple hundred $$$, so you might check that out.

Thanks everyone. I'm going to clean up the contacts, etc. and see if can get this operating myself. If not, I'll contact Benmar.
I have some Benmar manuals thanks to "SAM" here on the trawler forum.

Hi FOG,
I have the Benmar 21R in my PCF40. What I like about it is that is fully repairable at sea... except for the compass unit. The compass has a light sensor and a light. In between is a compass card that has a few black lines to mostly black lines that control the amount of light getting to the sensor based on the course. Looks like a 0.2 to 6v signal (might have been 8v) depending on how much light gets to the light cell. The weakness is in the compass card where the ink tends to fade from the card and no easy way to open and service. I’m in the process of converting it to a digital compass card. Not high on my priority list, but first run of the conversion worked, but was way to sensitive. Next version will have a wider control band to let the direction stabilize. All of the transistors and other parts are off the shelf. I keep spares on board, but since the rebuild, it has worked well. Also, installed a wireless remote that works great from anywhere on the boat. You’ll enjoy working on it. They are tough units built to last. Let me know if you have any questions.

Fredribt said:

Hi FOG,
I have the Benmar 21R in my PCF40. What I like about it is that is fully repairable at sea... except for the compass unit. The compass has a light sensor and a light. In between is a compass card that has a few black lines to mostly black lines that control the amount of light getting to the sensor based on the course. Looks like a 0.2 to 6v signal (might have been 8v) depending on how much light gets to the light cell. The weakness is in the compass card where the ink tends to fade from the card and no easy way to open and service. I’m in the process of converting it to a digital compass card. Not high on my priority list, but first run of the conversion worked, but was way to sensitive. Next version will have a wider control band to let the direction stabilize. All of the transistors and other parts are off the shelf. I keep spares on board, but since the rebuild, it has worked well. Also, installed a wireless remote that works great from anywhere on the boat. You’ll enjoy working on it. They are tough units built to last. Let me know if you have any questions.

Click to expand...

Thank you for the great explanation. You have put in a tremendous effort in figuring out the system. It all makes sense to me.
We are doing the Great Loop now and I’ve been busy with other issues, so unfortunately I haven’t had a chance to look at my system any further.
Hopefully I’ll get to it before we have to cross a section of the Gulf in Florida this November. Right now some of my tracks look as though I’ve been tacking a sailboat. Lol

FOG,


I was having a similar issue and after troubleshooting the problem for a while it seems to have settled down. I suspect that it was either caused by some air bubbles in the oil that was getting in the way of the light sensor or the mechanical cable that runs from the helm down to the compass unit was sticky. When I get a chance my plan is to disassemble the mechanical cable and give it a good cleaning and grease it.

Benmar autopilot

I realize that this is an old post but I would love any schematior wiring diagram you may have
William Michels

Contact Benmar. They are still in business. Somewhere in CA I believe.

Sorry I don’t have a diagram.
Last I heard they were in Santa Ana, CA.

Are you looking for a diagram on how to install the course setter in a boat, or how to troubleshoot an installation? I have a course setter 21 and let me know if you are looking for some basic hookup info.

Benmar has been very helpful if you can get them on the phone. They are now located in Idyllwild CA. Below is there contact information.

Benmar Marine
25510 Foster Lake Rd.
PO Box 4007
Idyllwild, CA 92549-4007

Phone: (951) 659-8510
Fax: (951) 659-8576
E-Mail: BenmarMarine@aol.com

Fredribt said:

Hi FOG,
I have the Benmar 21R in my PCF40. What I like about it is that is fully repairable at sea... except for the compass unit. The compass has a light sensor and a light. In between is a compass card that has a few black lines to mostly black lines that control the amount of light getting to the sensor based on the course. Looks like a 0.2 to 6v signal (might have been 8v) depending on how much light gets to the light cell. The weakness is in the compass card where the ink tends to fade from the card and no easy way to open and service. I’m in the process of converting it to a digital compass card. Not high on my priority list, but first run of the conversion worked, but was way to sensitive. Next version will have a wider control band to let the direction stabilize. All of the transistors and other parts are off the shelf. I keep spares on board, but since the rebuild, it has worked well. Also, installed a wireless remote that works great from anywhere on the boat. You’ll enjoy working on it. They are tough units built to last. Let me know if you have any questions.

Click to expand...

Please share more info on the wireless remote. That would be dandy !
Thanks,

Didn't read all the posts so maybe you got your answers.
Yes, the fluid is suppose to be there.
The compass sends its signal by a bulb shining through it onto a photocell through a variable density "film" (black to clear)

Benmar course setter 21 autopilot

Hello,
I would like to reinstall this autopilot and check it.
Unfortunately I haven't got the manuals.
I would like to ask for your help, if anyone can help me to get copy of the :

1. Course Setter Auto Pilot - Pilot House Control, Installation, Operation and Maintenance Manual

2. Course Setter 21H - Auto Pilot Power Unit Installation, Operation and Maintenance.

Thanks for your attention

Try contacting Benmar. They may be able to provide manuals for you.
http://www.benmarmarine.com/

Portage_Bay said:

Try contacting Benmar. They may be able to provide manuals for you.
http://www.benmarmarine.com/

Click to expand...

Thanks,
Already done, but didn't get any answer.
So, my last chance is to get in contact with someone who has the same equipment and manuals

Vince
I have the manuals you are looking for and could make you a copy. Send me a PM with your contact information.
Doug