Help with understanding Cetrek and GPS autopilot compatibility

Hello everyone,

I’m in need of advice and opinions. I’m currently looking to upgrade the electronics on my boat (1986 - 41’ motorboat). I’m normally able to research things and understand the basics, but all the options and brands of electronic equipment has me perplexed and nervous of buying something I can’t use or won’t work with what I have. I’m planning on installing everything myself, and prefer it so I will know where to look and back track if any problems come about after the installation. I’m pretty confident on doing the install, and absolutely terrified of learning the operation. These marine electronics have so many functions, it’s a bit intimidating for a novice as myself.

Where I’m confused is how my Cetrek autopilot (looks factory installed from 1986) can link to a new GPS. I can’t seem to locate compatibility between old and new. If possible, I would like to use my existing Cetrek auto pilot, but with a modern GPS. Does anyone have any info to share or experience updating electronics and using an older existing auto pilot. Do the electronics have a plug and play ability between brands and years, as far as cords or connections are concerned?

Secondly, If I use a new and current multifunction display, does that create an issue trying to incorporate the older systems I’m trying to keep. I would really like to be able to have a radar, GPS, and depth finder and then use my existing autopilot on a multifunction screen.I would like to replace everything at once, but I may need to do it in steps and want to use a brand that I can add systems to as needed or funds are available.

I’m at the unfortunate situation of not being to do a haul out currently. I’m hoping to use my existing transducers until I can do a haul out and change through hulls and update transducers, but not sure if that’s possible. Are the older versions of transducers compatible with anything new or does it all have to be changed? I mainly need a depth finder to navigate a river bottom.

Should I even consider upgrading electronics until I’m able to change transducers? I may just try to find a new head unit to my old depth finder if all this is a pipe dream. Any advice or opinions you guys have would be greatly appreciated.


All the best,

Sam

You could buy something like the Garmin Reactor 40 AP retrofit kit and use your existing AP pump. That would save you around $1000. Still have to spend about $2000 though.

Sam said:

Hello everyone,


These marine electronics have so many functions, it’s a bit intimidating for a novice as myself.



Where I’m confused is how my Cetrek autopilot (looks factory installed from 1986) can link to a new GPS. I





All the best,



Sam

Click to expand...

I am also trying to figure this out as I also have a reliable old Cetrek which is a very good autopilot, holds heading well and minimal pump activity.

It has an 0183 in capability that appears to have been connected to a laptop computer, but it was not connected to the current Simrad multi function plotter.

Some pointers on how to do this would be valuable to me as well.

Bill

Barking Sands said:

You could buy something like the Garmin Reactor 40 AP retrofit kit and use your existing AP pump. That would save you around $1000. Still have to spend about $2000 though.

Click to expand...

Thank you for the recommendation. I’ll give that some research.

Sam said:

Where I’m confused is how my Cetrek autopilot (looks factory installed from 1986) can link to a new GPS. I can’t seem to locate compatibility between old and new. If possible, I would like to use my existing Cetrek auto pilot, but with a modern GPS.

Click to expand...

What would that gain you?

Does your Cetrek AP work for holding a given course? "Go straight" mode?

-Chris

Island Cessna said:

I am also trying to figure this out as I also have a reliable old Cetrek which is a very good autopilot, holds heading well and minimal pump activity.

It has an 0183 in capability that appears to have been connected to a laptop computer, but it was not connected to the current Simrad multi function plotter.

Some pointers on how to do this would be valuable to me as well.

Bill

Click to expand...

The concept is simple. The implementation maybe not so much. As the tech who taught me how to handle NMEA 0183 said when we struggled with a setup "Welcome to serial port hell!"

You'll need to spend some time with the Simrad MFD and Cetrek manuals. You're looking for:

• Does the Simrad have NMEA 0183 out? If not perhaps you can find a converter that will work.
• What NMEA sentences does the Cetrek require?
• Can you configure the Simrad NMEA out to send the correct sentences?

You may need a connector on the Simrad end. If it's an older model Simrad Ebay may be your source. The Cetrek end is likely a place to connect two bare wires.

NMEA 0183 wiring is simple. Just two wires. When working 'blind' you have a 50/50 chance of getting it right. If the AP doesn't respond to the Simrad signals try reversing the connections.

If it still doesn't work try the easy stuff first. Are the Cetrek switches in the correct position? Is the Simrad set to output AP commands? Are the connector and wires securely set? Are the wires between the Simrad and the Cetrek near a source of electromagnetic interference?

If still no joy then you've got some detective work to do. A serial terminal emulator for your laptop and some fiddling with comm ports will allow you to 'see' the output from the Simrad. There is lots of info on NMEA 0183 sentences available online. This will tell you if the Simarad is putting out data that can be read by the Cetrek. Remember the reverse the connections idea if all you get on the terminal screen is goobldy-gook.

If you are certain that the Simrad output is what the Cetrek needs and still no joy then the problem is with the Cetrek and at this point I'm out of ideas.

Portage_Bay said:

The concept is simple. The implementation maybe not so much. As the tech who taught me how to handle NMEA 0183 said when we struggled with a setup "Welcome to serial port hell!"

You'll need to spend some time with the Simrad MFD and Cetrek manuals. You're looking for:

• Does the Simrad have NMEA 0183 out? If not perhaps you can find a converter that will work.
• What NMEA sentences does the Cetrek require?
• Can you configure the Simrad NMEA out to send the correct sentences?

You may need a connector on the Simrad end. If it's an older model Simrad Ebay may be your source. The Cetrek end is likely a place to connect two bare wires.

NMEA 0183 wiring is simple. Just two wires. When working 'blind' you have a 50/50 chance of getting it right. If the AP doesn't respond to the Simrad signals try reversing the connections.

If it still doesn't work try the easy stuff first. Are the Cetrek switches in the correct position? Is the Simrad set to output AP commands? Are the connector and wires securely set? Are the wires between the Simrad and the Cetrek near a source of electromagnetic interference?

If still no joy then you've got some detective work to do. A serial terminal emulator for your laptop and some fiddling with comm ports will allow you to 'see' the output from the Simrad. There is lots of info on NMEA 0183 sentences available online. This will tell you if the Simarad is putting out data that can be read by the Cetrek. Remember the reverse the connections idea if all you get on the terminal screen is goobldy-gook.

If you are certain that the Simrad output is what the Cetrek needs and still no joy then the problem is with the Cetrek and at this point I'm out of ideas.

Click to expand...

Wow, thanks for the detailed reply. I will read up, and connect up! I hope I didn’t hijack the OP’s question.

Bill

ranger58sb said:

What would that gain you?



Does your Cetrek AP work for holding a given course? "Go straight" mode?



-Chris

Click to expand...

Without data from a plotter the Cetrek can only hold a magnetic heading. The goal is to hold a course corrected for wind, tide, etc. with input from the gps via the plotter.

The reason I have never bothered to hook up the 0183 is because holding a heading gives you the lion’s share of the value of the autopilot, and one can argue that the ability to follow a course only allows an additional level of inattention that is irresponsible anyway…..let’s not open that debate here. The OP and I only look for experience and advice on how to hook up the hardware[emoji1]

Island Cessna said:

The reason I have never bothered to hook up the 0183 is because holding a heading gives you the lion’s share of the value of the autopilot, and one can argue that the ability to follow a course only allows an additional level of inattention that is irresponsible anyway…..let’s not open that debate here. The OP and I only look for experience and advice on how to hook up the hardware[emoji1]

Click to expand...

-Chris

Thank you all for your input.

Portage_Bay, that gives me some great info to research and a good starting point for diagnostics. If you give me a hammer and nails, I’m at home. When we start talking data ports and signals, my brain isn’t wired so well. I greatly appreciate your time in giving me some direction.

Island Cessna, by all means please ask your questions. I looked for information on this for a week or so and finally relented and posted here. I’ve read quite a few boats still use the Cetrek and found some repair shops in the process. This thread may pop up for someone else looking for Cetrek or older auto pilot integration help.

Ranger58sb- Like Island Cessna said, having the auto pilot connected for corrected course is the goal.

Sam

Island Cessna said:

Without data from a plotter the Cetrek can only hold a magnetic heading. The goal is to hold a course corrected for wind, tide, etc. with input from the gps via the plotter.

Click to expand...

Sam said:

Ranger58sb- Like Island Cessna said, having the auto pilot connected for corrected course is the goal.

Click to expand...

Still thinking about this... partly because our situation is similar: old-ish AP, not currently networked with either plotter.

I don't think I knew an autopilot could be "course corrected" with wind and tide info from a plotter. And our plotters don't have any wind info, anyway, no sensors for that.

Even though I'm mostly too lazy to do it, I do know about laying out a route in advance on the plotter (tried that approx once), or at least a waypoint to aim for, guiding a networked AP... Is that what you're meaning?

-Chris

I don’t have a lot of knowledge about it, but what I’m thinking is if I put the GPS cords in, it would adjust the rudder using the GPS location of the boat. Meaning if the boat was pushed by the tides or the wind, it would auto correct itself based mainly off the GPS coordinates of the boat relative to the GPS heading.

My last long voyage was spent manning the helm for 22-26 hours with out the GPS working and the auto pilot had a wire that came loose that I couldn’t trace underway. It was 6 days of little sleep, bad weather, and a sea sick wife. This was a sail boat before we moved to the trawler. We are hoping to move aboard next year and I’m doing everything I can to keep my wife comfortable and happy and also not spend the days watching the compass constantly. Based on my last experience, I believe if all the systems are working well, we will both be happy.

Sam said:

I don’t have a lot of knowledge about it, but what I’m thinking is if I put the GPS cords in, it would adjust the rudder using the GPS location of the boat. Meaning if the boat was pushed by the tides or the wind, it would auto correct itself based mainly off the GPS coordinates of the boat relative to the GPS heading.

Click to expand...

Ah. Right. Enter a waypoint in the plotter, let the AP drive to the waypoint. Got it.

(No direct wind/tide/current info needed for that.)

-Chris

I wasn't before, but am now a firm believer that unloading steering tasks from the operator of a boat allows for much better situational awareness due to increased time with "head out of the cockpit." I did not begin sleeping at the helm the day I connected my old AP to the chartplotter. In my case the only thing left of my 1972-era Benmar-Cetek AP was the electric motor driving the cable steering system. I bought the SITEX digital AP brain and the control heads and plugged them in to the plotter via two NMEA 183 wires and two wires to the old motor controller, and that was it - just worked.

I am new to APs which is a understatement. When I bought my boat 2 years ago the past owner installed a all Simrad AP setup. My friends that were better than I were all said that it held a course better than there setup. One friend with a 55' installed the same computer and controller and is more than happy with it. Of course a different pump!

If you have ever been thought the Cope Cod Canal the current and waves can push you around. I must say, it does a great job keeping the boat straight!