Upgrading chartplotter

Bucksribster · 01 January 2017, 17:02

I'm thinking of upgrading my old Garmin GPSmap 188c chartplotter to a 7-inch unit over the winter. My questions are around whether I will be able to use the new plotter with my existing transducer (in-hull mounted in the sump) and DSC radio (an Icom IC-M421).

I had a chat with a chap on the Garmin stand at the Southampton boat show, and he said that he thought that the Garmin Echomap Chirp 75dv would probably be compatible, but it depended on the connection to the existing unit, and I might need an adaptor cable.

It is a little difficult to trace the wiring from the existing unit as it is bound together in the harness soon after the back of the unit.

I am not really bothered about the sonar resolution etc, just really getting a depth beneath the boat. I would like it to give the position information to the VHF. I would like to use the existing transducer, as it is bonded in, and the wiring may be difficult to pull through.

Does anyone have any experience or advice on this type of upgrade?

Bucksribster · 05 February 2017, 17:54

I never had a reply to this thread, which makes me think it may not be a simple DIY job. Is there any recommendations for someone who might do the upgrade for me for a gentle price? Or am I better off sticking with what I have, i.e. the old Garmin unit, supplemented with an ipad mini running Navionics?

jeffstevens763@g · 05 February 2017, 18:06

Hi mate missed this one can't really answer fully but I would upgrade with a new transducer not east to pull through but not that difficult take the old out but leve a thin rope in its place then pull through with that it needs two really so it can be fed properly and pulled back if it gets stuck and work it through I've done three is way.

Cheers

Bucksribster · 05 February 2017, 18:12

Quote:

Originally Posted by jeffstevens763@g

Hi mate missed this one can't really answer fully but I would upgrade with a new transducer not east to pull through but not that difficult take the old out but leve a thin rope in its place then pull through with that it needs two really so it can be fed properly and pulled back if it gets stuck and work it through I've done three is way.

Cheers

Thanks for this Geoff - I guess a new transducer will probably be cheaper that getting someone to fit it. The old transducer is glassed into the bottom of the boat, so I guess I would need to cut it out, and re-glass in a new one?

jeffstevens763@g · 05 February 2017, 18:24

Unless you go transom mount with the new one personnely I've had both and don't see any difference in performance.
My last through hull was sikaflexed in the one before epoxied in so not bad to remove.

willk · 05 February 2017, 20:30

Have you got space for a second plotter? If so, I'd keep what you have and pop in a cheap "plotter only" and share the depth data over nmea0183.

Otherwise - I'd try to maintain an in-hull transducer. The housing may fit a new transducer head (they just screw in). I'd ask Garmin about a conversion cable too. Make sure you're sitting down for that call!

Everything should talk over NMEA0183 - if you have patience and good colour vision.