Bottom contour mapping via dinghy

[geoffschultz]

I've been taking my 5'5" draft Freedom 40/40 in & out of the Rio Dulce in Guatemala since 2001 and have never had a problem. There's a bar at the entrance that's probably 1/4 mile wide and we always cross at the astronomical highest tides of the month. Last year we bumped very hard multiple times when going out and we had to get pulled across using 2 dinghies with 15 HP motors to make it in. We have a 6' wide wing keel, so heeling the boat doesn't help.

I've been using the same/current waypoints for years, so I suspect that the channel has moved or silted in. My goal is to take a dinghy out with some kind of sounding device to map the bottom contour before trying to take BlueJacket out through it.

Does anyone have suggestions for a reasonably priced solution to this? In the past I've just taken a hand held depth sounder and a handheld GPS and mapped things that way, but I was looking for something more automated.

Thanks, Geoff

 

[BarryL]

Hey,
Navionics does this for you. I have a B&G plotter with Navionics chip and sonar transducer. I run the Navionics app on my phone and my phone connects to my plotter. The phone saves the sonar logs and then uploads to Navionics. After a few days they process it and update the charts. Anytime I run the Navionics app on my phone I get updated crowd-sourced data from the cloud.
Navionics does have a free chart viewer that runs on Windows, Android and iOS devices. You can take a look and see what the already have for that area.
I'm not sure what exactly you would need to be able to collect and upload data from your boat. Probably just a basic cheap plotter with a simple sonar transducer. I can look into it in more detail if you want me too.

Barry