Sharing soundings between dinghy and yacht

[Jammer]

What is the best practice for recording depth data while exploring an area with a dinghy and then having that data available for navigation?

I've experimented with Navionics Sonarchart but it requires an internet connection and there is a week-long delay while the sonar logs are processed, approved, and distributed.

[belizesailor]

Lead line and a pencil and paper works pretty good....or voice notes on a smart phone.

[SailRedemption]

Hummingbird helix units can record bathometric data I like believe. They may have smaller portable units for small boats that may do the same.

[AedanC]

Assuming your dinghy has a plotter you could put a NMEA data logger on it and use that to transfer the data to another device. You would need to log the GPS location as well as depth.

[belizesailor]

I used to have a cool little depth transducer which could be cast by a spinning rod or trolled on a line. The newer generation of these use smart phones with fish finder like apps and have the ability to archive data. There you go.

https://www.outdoorlife.com/articles...ar-fishfinders

[Jammer]

Thanks for the replies.

At present I have a Vexilar transducer and wireless sonar which I am using with an android smartphone. I run the Navionics app. It does collect GPS and depth data, and updates charts on the smartphone in real time, and then (usually) eventually uploads the data to Navionics. The trouble with this is that there's no way to copy the data to a chartplotter without waiting for a week to go by, since that is how long Navionics sits on the updates before distributing them.

[belizesailor]

It would be interesting to know how Navionics reconciles that data for areas where they charts are inaccurate.

Ive tried reporting imaccuracies to them...bottom line: they dont want to know.

Maybe sending some soundings of inaccurate areas would get their attention...hey look, its 20' deep ashore!

[Olddave]

Originally Posted by Jammer

Thanks for the replies.

At present I have a Vexilar transducer and wireless sonar which I am using with an android smartphone. I run the Navionics app. It does collect GPS and depth data, and updates charts on the smartphone in real time, and then (usually) eventually uploads the data to Navionics. The trouble with this is that there's no way to copy the data to a chartplotter without waiting for a week to go by, since that is how long Navionics sits on the updates before distributing them.

Jammer
The easy answer is to move your plotter between the the two vessels.
Otherwise Maxsea software will do it easily but not without some expense. Maxsea/Furuno is very good gear, check out Time Zero Plot. That is what commercial fishers use.
Dave

[Jammer]

Originally Posted by belizesailor

It would be interesting to know how Navionics reconciles that data for areas where they charts are inaccurate.

Ive tried reporting imaccuracies to them...bottom line: they dont want to know.

Maybe sending some soundings of inaccurate areas would get their attention...hey look, its 20' deep ashore!

Navionics accumulates sonar data from its users and publishes the results as "Sonarchart" data. This is bathymetric data only. They do not revise shoreline/riverbank boundaries based on it. However, they will source shoreline/riverbank data for previously uncharted areas when they receive sonar data for a new area.

When you view their charts, whether on the web, in an app, or on a plotter, you can select which bathymetric layer you want to see. In most cases, that will be a choice of their data, or the sonarchart data. On a chartplotter or in the app you may also see a government chart layer, but they don't expose it in the web app.

This is all fine for general planning or finding fish. I don't necessarily trust it to get me through a marginal channel with a larger boat.

[Jammer]

Originally Posted by Olddave

Jammer
The easy answer is to move your plotter between the the two vessels.

Not sure if that's practical in my situation. Maybe.

Otherwise Maxsea software will do it easily but not without some expense. Maxsea/Furuno is very good gear, check out Time Zero Plot. That is what commercial fishers use.
Dave

Thanks, that helps.

[Redline452]

I second the lead line... the spots I've tried to sound out with a handheld (flashlight-style) depth sounder, I got a lot of low readings due to seaweed. Even the "big boat" instruments have said she was anchored in 4 feet of water, which is physically impossible without digging a two-foot hole in the bottom. Swing a few feet over, and depth was back to 10!

Given that the seaweed grows over the summer, I've often wondered how Navionics, Garmin et al correct for that, if at all.

[belizesailor]

Originally Posted by Redline452

I second the lead line... the spots I've tried to sound out with a handheld (flashlight-style) depth sounder, I got a lot of low readings due to seaweed. Even the "big boat" instruments have said she was anchored in 4 feet of water, which is physically impossible without digging a two-foot hole in the bottom. Swing a few feet over, and depth was back to 10!

Given that the seaweed grows over the summer, I've often wondered how Navionics, Garmin et al correct for that, if at all.

All the fancy electronics are handy, but I still carry a small lead line just for those sorts of situations. Turbid shallow water can also confuse sonar.

[Mike_Thor]

Jammer, we are permanent live-aboards and are constantly sailing the East Coast of Australia including the various (numerous) reef systems. After a (very) long discussion with Raymarine, Navionics (Product Mgr level) and several interested retailers it has been concluded that:
a. Any uploaded cartography to Navionics will be incorporated into their next 'download' (provided you have a current licence);
b. They may / do not accept 100% of depth variation data (to avoid significant changes occurring due to one false reading I understand);
c. You cannot 'get at' any of your SonarChart (r) data if using iOS. Chart sync etc will transfer it but there is no 'public access' to this file.

Because we are working around significant reef systems; ocean / river bars and generally into tight spots we have forked out the funds for the following system.

Raymarine A68 Hybrid touch MFD plus a chirp transponder. Sonar Chart logging on; bottom lock and set the transponder depth (-100 mm); tidal adjustment on.
I use a spare 12 V battery and secure the lot into the dingy (<5 mins).
I have already taken out the current Navionics chart chip (microchip) and installed it into the A68 when onboard the main vessel so that I don't end up dropping the lot into the ocean.
Turn on track and run around in the dingy (around 9-11 kts) and 'survey' the area. See Navionics FAQ for how to undertake a 'survey' (i.e. the route your actually cover).

Back on board I simply de-install and then swap out the chart chip back to the Raymarine E7D. I now have networked SonarChart Live(r) data for navigation. I use it regularly to record very tight navigation access etc. and/or 'escape' routes if I need to dash in the middle of the night and do not want to follow the inbound tortuous route (had track on).

This is not the cheapest solution but the cost of running into something is really easily covered. It has allowed us to go into fantastic spots in the reef system and up rivers etc. As always keep Mk1 eyeball on the latest lateral marks but we are heavily reliant on it to keep us floating.

[CaptTom]

Originally Posted by Jammer

At present I have a Vexilar transducer and wireless sonar which I am using with an android smartphone.

Personally, I'd use the android phone to navigate on board the "mother ship" in areas where you need the recently-collected depth data. Buy a tablet instead, or cast the display to a larger monitor, if you really want a larger display.

It's cool to see these technologies starting to mature. At some point, hopefully, what you really want to do will become a reality out of the box.

[Jammer]

Thank you for the replies. This provides some options and real world experience.