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Flyingriki · 05-03-2018, 08:11

Per a recommendation here I found a discontinued Garmin 840xs. Seems like a fabulous unit!

All my old instrumentation is Autohelm and Raymarine. Is any of that capable of being used with the Garmin or must I replace everything? Wind sender is shot so I'll replace that but will the same wiring in the mast be OK or do I have to pull something new? And how about depth, speed, autopilot etc....?
Thank you!

**skipmac** · 05-03-2018, 09:03

Quote:

Originally Posted by Flyingriki

Per a recommendation here I found a discontinued Garmin 840xs. Seems like a fabulous unit!

All my old instrumentation is Autohelm and Raymarine. Is any of that capable of being used with the Garmin or must I replace everything? Wind sender is shot so I'll replace that but will the same wiring in the mast be OK or do I have to pull something new? And how about depth, speed, autopilot etc....?
Thank you!

Whether you can use the old equipment with the old/new Garmin depends on what you want to do with it and also what models of the old equipment.

The Autohelm depending on the model, if all the bits are there and working will keep working. You will probably not be able to connect it to the GPS to track to a waypoint but still can set a compass course to follow on the Autohelm, again assuming all the components of the Autohelm are there and working.

The other electronics, if they have NMEA 0187 or NMEA 2000 connections you should be able to interface all the different brands to speak to each other. May take a bit of learning and tinkering but it can be done.

Pizzazz · 05-03-2018, 09:47

You can get a new 0183 wind sensor from NASA Marine for about $200. You can use the existing wiring as the new sensor only uses three wires. You can then feed the sensor into the Garmin and the Garmin into the autopilot. If the autopilot is connected to your wind sensor display via Seatalk, the display will repeat wind speed and direction. For depth, there is no practical and cheap way to get the Seatalk data to the Garmin. Either use your existing depth display as stand alone or add an inexpensive ($100) sonar sensor to the Garmin. You can mount it in hull. This way you have redundancy. For speed, there is no practical solution. You will need to replace the sensor with a nmea 2000 version.

**skipmac** · 05-03-2018, 10:03

Quote:

Originally Posted by Pizzazz

You can get a new 0183 wind sensor from NASA Marine for about $200. You can use the existing wiring as the new sensor only uses three wires. You can then feed the sensor into the Garmin and the Garmin into the autopilot. If the autopilot is connected to your wind sensor display via Seatalk, the display will repeat wind speed and direction. For depth, there is no practical and cheap way to get the Seatalk data to the Garmin. Either use your existing depth display as stand alone or add an inexpensive ($100) sonar sensor to the Garmin. You can mount it in hull. This way you have redundancy. For speed, there is no practical solution. You will need to replace the sensor with a nmea 2000 version.

Excellent information but a couple of comments. On the Autohelm I had a very old unit that came on my boat I and I don't believe it had any NMEA connections at all, stand alone unit only.

Also, I have Raymarine Seatalk1 speed and depth and have linked them to my new Garmin. If you have a Raymarine display for speed and depth like and ST60 Bidata you can buy converters from Raymarine that connect to the Bidata display and convert Seatalk1 to SeatalkNG and/or NMEA2000 and/or NMEA 0183 (not 0187, sorry for the previous typo).

Pizzazz · 05-03-2018, 11:06

You can convert Seatalk1 to nmea2000 ($100 converter) and you can buy an active sense or similar nmea 0183 to nmea2000 converters ($200) But at that point it is not becoming practical, i.e. you are better off selling the Garmin and buying a Raymarine a78 or similar unit. If you have such an old autohelm unit you might be better off selling it for an st4000+ then hooking it up via nmea.

Upgrading older electroncs is a difficult trade-off. Either you stay with Seatalk1/nmea0183 and use st4/5/6000 units to convert or you go to nmea2000. If you stay in the middle and invest in converters, etc. you spend more, waste a lot of time in splicing wires and don't save anything. Been there, done that.

**skipmac** · 05-03-2018, 14:58

I agree in a lot of cases it isn't worthwhile to spend for the converters but in some cases it is. New speed and depth transducer(s) are a lot more than the converter, in my case starting about $300 and going up from there depending on the model and range. Also using the converter doesn't require a haul out and/or pulling new cables over under around and through the boat.

Quote:

Originally Posted by Pizzazz

You can convert Seatalk1 to nmea2000 ($100 converter) and you can buy an active sense or similar nmea 0183 to nmea2000 converters ($200) But at that point it is not becoming practical, i.e. you are better off selling the Garmin and buying a Raymarine a78 or similar unit. If you have such an old autohelm unit you might be better off selling it for an st4000+ then hooking it up via nmea.

Ditched the Autohelm and bought a Simrad. I did keep the the original linear drive which works just fine.

Upgrading older electroncs is a difficult trade-off. Either you stay with Seatalk1/nmea0183 and use st4/5/6000 units to convert or you go to nmea2000.

Skipped 0183 and went straight to 2000. It's all plug and play except for interfacing with Raymarine's version, SeatalkNG which uses proprietary cables and takes a little adapting.

If you stay in the middle and invest in converters, etc. you spend more, waste a lot of time in splicing wires and don't save anything. Been there, done that.