Surveying Anchorages in Uncharted Waters from the Dinghy

[Dockhead]

Something someone said in another thread made me think of this --

Has anyone used a handheld depth sounder from the dinghy, to survey a questionable anchorage before entering with the mother ship?

I would think there should be some way to record the data, reference it to GPS coordinates, and display the results on a chart. This could be really useful in places like the Baltic archipelagoes, where the waters not used by ships are poorly surveyed or not surveyed at all, and where the bottom is rocky and subject to huge and sudden changes of depth.

[IdoraKeeper]

Certainly! There are many places in the PNW where charts disagree with reports of groundings on unknown obstructions. There are also moorings that are known to be obstructed at low tide. We use a lead line and tide charts to time arrival and departure.. It is also necessary to know exactly what the correction needs to be to account for transducer placement.

[IdoraKeeper]

Note... This dates can be added to Navionix charts.

[s/v Moondancer]

When I take my 7-6 ft draft across the Bahama Banks we use the dinghy and handheld depth finder when we get off the known safe transit lines to anchor. I have met cruisers with fish finders mounted in the dinghy. Never seen anyone use a recording device.

We have used the handheld to chart exits off the Banks when we doubted the charts.

[sea-bee]

I've just installed a smart little chartplotter in the dinghy. It only has a little 4" screen, but it has a built in wifi hotspot. The Raymarine Dragonfly Pro has Navionics chart card and communicates with Navionics on a tablet, updating the sonarcharts as we drive around. Bring the tablet back on board the yacht, and there is the detail needed to navigate with confidence.

Chris

[Pete7]

Thought this had been raised before:

https://www.teamsurv.com/

There may be other crowd sourcing systems gathering data.

Also one man and his dinghy surveying Scotland, very commendable

Antares Charts: One man's mission to update Scottish charts - Practical Boat Owner


Pete

[Dave_S]

I don't have it yet so I can't comment on how good or bad it is except that you can update your Navionics charts on the boat from a micro SD card that you use in a depth sounder in your tender. It logs depth and GPS which comes across onto your maps.

Hopefully it works.

[Dockhead]

Originally Posted by sea-bee

I've just installed a smart little chartplotter in the dinghy. It only has a little 4" screen, but it has a built in wifi hotspot. The Raymarine Dragonfly Pro has Navionics chart card and communicates with Navionics on a tablet, updating the sonarcharts as we drive around. Bring the tablet back on board the yacht, and there is the detail needed to navigate with confidence.

Chris

OK, that's cool. So you are concretely doing what I asked about, and you do it using the Navionics Sonarcharts technology. Great; I'll look into that. Meanwhile it would be great if you could provide concrete details of how it works and what the procedure is.

[KRMS]

Originally Posted by Pete7

Thought this had been raised before:



https://www.teamsurv.com/



There may be other crowd sourcing systems gathering data.



Also one man and his dinghy surveying Scotland, very commendable



Antares Charts: One man's mission to update Scottish charts - Practical Boat Owner





Pete

Let me add another shout out for Bob Bradfield and his Antares Charts of the western isles of Scotland. He has surveyed more than 700 anchorages in fabulous detail. The charts are available in various formats to display on Memory Map charts and on OpenCPN etc. We used them extensively last year and managed to park in some really remote locations that I wouldn’t have had the courage to enter without these charts. Bob is a really nice chap as well so I’m sure he’d be happy to share his knowledge if you wanted to seriously get into this.

[brianc]

Originally Posted by IdoraKeeper

Certainly! There are many places in the PNW where charts disagree with reports of groundings on unknown obstructions. There are also moorings that are known to be obstructed at low tide. We use a lead line and tide charts to time arrival and departure.. It is also necessary to know exactly what the correction needs to be to account for transducer placement.

Is there a list of these somewhere? I'd like to not find one accidentally...

[toddster8]

Lots of skinny water around here. I've been considering buying the Garmin Echomap 44cv for (in part) exactly this purpose. It has automatic mapping software and can be rapidly transferred between the cockpit and the dinghy - or even a kayak or SUP. Though it does require an external battery.
I'd also like it to scout out dive sites.
Seems to often be on sale for about $250. This weekend at WM, for example.

Oh, I also have the "sonar phone" toy. Like an oversized fishing bobber that links to your phone. Doesn't do any mapping though. Every time I think of using it, it needs to be charged up (several hours via USB connector). "OK, maybe I'll take it next time."

edit: OK, the web site suggests that SonarPhone CAN be used with Navionics to create charts, but does not offer details.

[Mike OReilly]

Love the high tech solutions. Might look into that wifi gizmo. Sounds great.

I’ve surveyed an unknown area many times from the dingy, except I use our leadline. Very handy for those skinny, narrow anchorage entrances.

[mvmojo]

I had a project a number of years ago to outfit a remote controlled small electric boat with a depth sounder, gps module and a wifi transmitter. The idea was to drive the little boat around a potential anchorage or inlet and automatically chart the depths. Unfortunately, it never got out of the planning stages, but I still think it's a cool idea! Looks like the technology exists in a pre-packaged form with Sea-Bee's little chartplotter. Gotta think about putting one of those on an R/C boat....

[Dockhead]

Originally Posted by Pete7

Thought this had been raised before:

https://www.teamsurv.com/

There may be other crowd sourcing systems gathering data.

Also one man and his dinghy surveying Scotland, very commendable

Antares Charts: One man's mission to update Scottish charts - Practical Boat Owner


Pete

Thanks. I've now read all this with interest.

It requires quite a bit of production according to these methods to get the data into any kind of a chart. I think this is not quite what I am looking for.

If the Navionics system will allow the data to be uploaded straight into the plotter, then that would seem to be the way to go. I continue studying it.

[Tricolor]

Originally Posted by Dockhead

Thanks. I've now read all this with interest.

It requires quite a bit of production according to these methods to get the data into any kind of a chart. I think this is not quite what I am looking for.

If the Navionics system will allow the data to be uploaded straight into the plotter, then that would seem to be the way to go. I continue studying it.

https://depth.openseamap.org/ data logger used by open sea map.