Sailboat depth transducer - useful?

[sv_pelagia]

New survey data (for Canada) are coming....

Attached figure (left) is the current chart (in fathoms) for Burnaby (Dolomite) Narrows in Haida Gwaii. Not great!

On the right are unofficial ("not for navigation") survey data (in metres; "-0.7" = dries at 0.7m above datum) that will eventually be used for new chart.

[Mike OReilly]

Originally Posted by sv_pelagia

New survey data (for Canada) are coming....

Attached figure (left) is the current chart (in fathoms) for Burnaby (Dolomite) Narrows in Haida Gwaii. Not great!

On the right are unofficial ("not for navigation") survey data (in metres; "-0.7" = dries at 0.7m above datum) that will eventually be used for new chart. Attachment 230094

That's great. Do they publish a schedule of areas that will be newly sounded?

I'm not holding my breath for some of the more remote parts of the east coast. Even when I was up on Lake Superior there were areas that were still using 1800s soundings. Unless there is a commercial or military need, there's little value in resounding areas. They don't really care about us recreational types (nor should they).

[edexter]

Well the Chesapeake where we sail can go from deep to shallow pretty quickly, especially up in the Susquehanna Flats...Our little Rhodes 22 has a centerboard that rotates backward if struck, and pulls up into a keel stub to give you 2’ draft, so I haven’t bothered installing one. But we have a handheld model we just dip over the side so we can calculate scope.

[Nicholson58]

I have two. We weigh 40 tons, 58 feet. Not knowing the depth is not an option.

We also use depth to correlate where we are with data on the charts.

[sv_pelagia]

Originally Posted by Mike OReilly

That's great. Do they publish a schedule of areas that will be newly sounded?

I'm not holding my breath for some of the more remote parts of the east coast. Even when I was up on Lake Superior there were areas that were still using 1800s soundings. Unless there is a commercial or military need, there's little value in resounding areas. They don't really care about us recreational types (nor should they).

Mike,
You'd be surprised!

Check out:
https://data.chs-shc.ca/login agree the terms, then zoom in...

Note:
- NONNA stands for "Non Navigational"*
- NONNA 100 has 100-metre "accuracy"
- NONNA 10 has 10-metre accuracy

Last year, the West Coast was all NONNA 100. Now there is more NONNA 10. Looks like NL has more 100 than 10.

The downloads (I use xyz format) give you a ton (!) of numbers that must be manipulated. I use QGIS (plus SASPLANET etc).

I've checked the soundings with new/current charts, and the NONNA pretty much corresponds to chart. So, useful I think, even if officially "non Navigational".

I don't know when official charts come out. We saw them surveying Burnaby Narrows way back in 2011! Still no new chart.

Cheers,
David

[dmkkeng]

Originally Posted by Wckoek

Most of the boats I been to and sail didn't have underwater transducer, I think it might not be a necessity.
How many of you have transducer installed in your boat?
Would you find it useful or even necessary?

Very useful and absolutely necessary especially for anchoring or navigating narrow passages or shallow areas. Not only do I have one installed permanently in the boat, I also carry a portable depth sounder as backup or for checking depth at the back of the boat if I am stern tying to shore.

[sailingbare]

Have always had one. I use the "cheap fishfinder" variety on my trailer sailers.

[rossdv8]

I sailed in reef waters. In my last several yachts I installed fish finders. Two of my ex racing yachts had expensive depth sounders installed, but I found the fish finders to be more accurate, so replaced the depth sounders with them.

For firing through a fibreglass hull, I initially mounted the transducery thingy in clear or neutral or whatever it is called, Silicone Sealant.
In later boats I used a sealant product called 'All Clear'. It is like silicone, but some sort of ploymer. It is transparent, like glass, and if you use it carefully you can avoid bubbles under the unit that is usually in the water.

Working through the fibreglass was a bit of an issue, but not as much as I imagined it would. The main thing was to find a bit of the hull ahead of the keel, but thin enough to have less effect.
I found in my last boat that mounting it just ahead and to one side, but making sure it was vertical. it gave nice familiar readings in areas where I knew what the old ones had shown.

The only reefs I hit with these things was where I ignored the readings and decided i could sneak through, but forgot the waves were adding or subtracting a foot or two from the indicated reading.

[DocBrauer]

Most important instrument on my boat. Have 2 also.

[wesevans]

Always had a depth finder. An essential instrument in shallow water and a help in navigation inshore.

[mitiempo]

In the early 70's I had a depth sounder - but no other electronics. It was the kind with a rotating light on the display - not seen any more but it was not expensive and worked well.

Currently I have a depth sounder with the transducer epoxied into the hull ahead of the keel as well as a handheld for backup and use from the dinghy. I also have vhf, ais transponder, plotter, and radar. The one I would not want to do without is the depth sounder.

[sailingabe41ds]

...what was that American Express commercial in the 70s....oh, yes "don't leave home without it"

Abe

[Mike OReilly]

Originally Posted by mitiempo

In the early 70's I had a depth sounder - but no other electronics. It was the kind with a rotating light on the display - not seen any more but it was not expensive and worked well.

The first boat I owned came with one of these. It used a flashing red, strobe-like, light as the display. I never really worked, and I removed it and installed a more modern one, but I remember just being mesmerized by the flashy red dot. If I had been smoking whacky weed at the time I figured it would have made an awesome trip ... man.

[Scorpius]

Originally Posted by mitiempo

In the early 70's I had a depth sounder - but no other electronics. It was the kind with a rotating light on the display - not seen any more but it was not expensive and worked well.

Currently I have a depth sounder with the transducer epoxied into the hull ahead of the keel as well as a handheld for backup and use from the dinghy. I also have vhf, ais transponder, plotter, and radar. The one I would not want to do without is the depth sounder.

I've still got one of those oldies! Still works just fine. I keep it as a spare in case one of my more modern one fails.

[fcallard]

Originally Posted by Cheechako

You can get by without it on that shallow draft.... you'll see bottom before you run aground probably. On normal draft a depth sounder has kept me from running aground many times.

My boat will float in ~2’ of water (although it likes to have the swing keel down for sailing) and we keep it at a floating dock with 2.5 ft MLW.

Most of the time we can’t see the bottom when the depth is 2’ or more. Unfortunately the depth sounder does not register very shallow depths, so we refer to tide charts and visual references (in familiar waters) to save the bottom paint. When we are away from home in shallow water, we adjust the swing keel depth and “sail by Braille”. Having an electric keel winch and a foot pedal by the helm allows us to raise the keel on short notice.