[marvout]

I sail in an area with pathetic charting. I'd like to create my own depth charts by roaming an area with a dinghy and getting depth data connected to GPS coordinates. What hardware would I need to do that? I want to be able to see the GPS, or I could use a separate one to create a proper track, see where I've been. I don't mind doing some processing later on the PC to make this work. I'm not interested in doing it by hand, trying to corelate some handheld sounder number with spots on a hanheld GPS. I'd really like to just pilot the dinghy. I'm presuming the whole rig to be removable from the dinghy. What's the cheapest hardware set up that would do this?

Marvin

 

[Bill-Rangatira]

do a laptop with nmea tranducer and gps
simply record the data and cross reference the depth and coordinates via timestamps
you want a good gps to be very acurate
correcting of course for tide

 

[night0wl]

Sounds like you have the *PERFECT* use case for this:

Amazon.com: Vexilar SP300 T-Box Smartphone Fish Finder with Portable Case, Black: Sports & [email protected]@[email protected]@http://ecx.images-amazon.com/images/I/[email protected]@[email protected]@51yFFOb0ThL

A review of the potential uses here: Panbo: The Marine Electronics Hub: Vexilar T-Box WiFi fishfinder & Navionics SonarChart Live wow

Make sure you SHARE your depths and readings to benefit the world here:
OpenSeaMap*?*Water Depths hopefully your readings will improve http://openseamap.org/index.php?id=openseamap&L=1 such that we have open source free charts globally!

 

[Stumble]

The other option is to look into the Navionics SonarChart. It's basically crowd sourcing applied to chart data and allows anyone in the world to upload depth/GPS data to Navionics, then they take that data and update their charts every few weeks. Over time the goal is to remap the world, but in the short term a $250 set up can be installed on your dinghy and the entire area mapped. A few weeks later you can update the charts on your plotter and have high quality data of the area.

There are some issues with this, like the delay, and the individual ownership data of crowd sourced information. But it's a pretty slic system.

Take a look at Panbo: The Marine Electronics Hub: Vexilar T-Box WiFi fishfinder & Navionics SonarChart Live wow

 

[night0wl]

The other option is to look into the Navionics SonarChart. It's basically crowd sourcing applied to chart data and allows anyone in the world to upload depth/GPS data to Navionics, then they take that data and update their charts every few weeks. Over time the goal is to remap the world, but in the short term a $250 set up can be installed on your dinghy and the entire area mapped. A few weeks later you can update the charts on your plotter and have high quality data of the area.

There are some issues with this, like the delay, and the individual ownership data of crowd sourced information. But it's a pretty slic system.

Take a look at Panbo: The Marine Electronics Hub: Vexilar T-Box WiFi fishfinder & Navionics SonarChart Live wow

I have a huge problem with a commercial entity taking my sonar data and profiting/controlling it. I would share my data with openseamap so that eventually, we can cut the cord from these commercial providers taking OUR data (both community and government) and locking us in to a vicious upgrade cycle.

 

[Stumble]

Night owl,

I don't disagree at all. i would love one of the open source companies to wind up in the lead on this one.

 

[Noelex]

Depth sounders are getting very cheap.

I made a bracket with a Garmin 300c. It just drops over the stern of my tender. The transducer is one side of the bracket the display and 12v battery the other, so it is self contained.

It is helpful in tight, poorly mapped anchorages. It is easy to scan the area to check for any underwater problems. Combined with a laser rangefinder you can anchor with shallows only just outside the swinging circle.

This is not an automatic logging system like the OP wants, but is simple and cheap solution to identifying the hazards in an anchorage.

 

[ReefMagnet]

If you're a dabbler with computer programming, it should be possible to record an nmea data stream of depth, time and lat/long to a text file. This just needs a gps and transducer that emits nmea format data and a laptop to receive and record it. The file can then be processed (the tricky part) which would allow the addition of tide height (for LAT values of depth) and smoothing (to filter out surface chop). Then it's just a matter of getting it onto a chart.

 

[i_amcdn]

I cannot find it on his site now but I do recall reading how Walker Mangum created his own charts around Anegada Island, BVI using his dinghy, a sounding line and his GPS. The GPS charting there is based on British and Russian admiralty charts that are so old they can be dangerous. Walker's hand measurements were requested by the Brits so that they could update their charts.

Interesting readings are here>>>> Navigating With GPS, Charts, and Eyeballs
BVI GPS Waypoints

"A GPS knows precisely (within a few feet) where it is. But a GPS does not know precisely where anything else is!" Walker Mangum

 

[jtulls]

I agree with night0wl, it does sound like you are an ideal candidate for the Vexilar TBox that you can connect to the Navionics app with. There is also now a SonarCharts Live option too where you see the depth contour updates in real time on the app -- check out the video:

As a first step though, you can check out the Navionics SonarCharts on their webapp (Navionics Webapp). If the detail is more what you are looking for, just download the app (the free version won't give you the SonarCharts, but you can upgrade the app to get them) and use that! The cost of the app will save some bucks rather than buying the TBox unit if that's a concern.

 

[Leftbrainstuff]

We use our handheld depth sounder from our dinghy. It's only really practical for sounding around our mooring to find the shallower or deeper mooring spots.

We've used it in Angel Island at Ayala Cove as we touch the bottom on some moorings at low tide. We sometimes use it to confirm chart soundings on marina entries too.

Its a hawkeye unit.