older autopilot and loran c vs gps

[GB36-231]

Hi Cruisers,

I recently found a NOS Cetec Benmar Compu-course 220 that I will be installing on my boat. The input for auto-trac is set up for 2 wire Loran C data. Can this unit be made to work with the GPS signal running my OpenCPN nav software? I tried contacting the gentleman at Benmar Marine but the line is not in service anymore and the website says "temporarily closed". Let's hope it's just temporary!

TIA,

Randy Good
GB36-231

[goboatingnow]

The nmea sentences for loran are different then for gps so a con error would have to be sourced to do that , this assumes of course the loran input is NMEA to begin with !

[Bill O]

Randy is this like the one you found?

https://www.cruisersforum.com/forums...ot-136770.html
The large steering compass looks similar to an old Wood Freeman AP compass that was originally on our boat. Even though ours was a totally rebuilt WF AP, we ditched it for a newer, much smaller electronic AP, pypilot.
I see you already use opencpn, so you may be familiar with pypilot. It uses very sophisticated software to do more than a point and shoot AP. We've used it for years and it works well. https://phoenixketch.blogspot.com/se...abel/Autopilot

[GB36-231]

Hi Bill,

Yes, same model only new in the factory boxes and an octopus/benmar linear hydraulic drive unit. I did find in the manual that the APU was set up for nmea 0183, so there's that. The PyPilot looks amazing - my techie son can help me understand it maybe!

Thanks for the insight,

Randy

[flightlead404]

Originally Posted by GB36-231

Hi Cruisers,

I recently found a NOS Cetec Benmar Compu-course 220 that I will be installing on my boat. The input for auto-trac is set up for 2 wire Loran C data. Can this unit be made to work with the GPS signal running my OpenCPN nav software? I tried contacting the gentleman at Benmar Marine but the line is not in service anymore and the website says "temporarily closed". Let's hope it's just temporary!

TIA,

Randy Good
GB36-231

I don't know anything about that unit, but back in the 90's I built a little device that took loran/gps nmea output and converted it into the +L/+R format my ancient autopilot used.

If your unit uses a simple relative voltage mechanism to command left/right turns you could do it easily with a little code and an arduino type device.