Depth/Speed transducer location questions.

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Joined:Fri Oct 12, 2012 4:06 pm
Depth/Speed transducer location questions.

Post by prjacobs » Fri Dec 30, 2016 12:45 am

I'm planning on adding a B&G Triton Wind/Depth/Speed set of instruments to my Ballad.
Has anyone mounted a depth/speed transducer here?
bilge.jpg (29.9KiB)Viewed 12728 times
Are there problems with hull thickness, fairing the outside, or a chance of weakening the hull?
Would you mount on centreline or offset enough to miss the 'V' shape of the hull?
As always, any and all suggestions are welcome!

Joined:Fri Oct 12, 2012 7:47 am

Re: Depth/Speed transducer location questions.

Post by MarkRyan1981 » Fri Dec 30, 2016 9:40 am

Hello Peter,

Good to hear from you! My log is mounted here, offset from the V: ... ng-safely/

My depth transducer is mounted inside the hull, along the center-line, without any through hull. The B and G instructions show it set offset, and if you can do it that way, I'd do it that way every time: ... -001_w.pdf. Would that stop the transducer working on one tack tho? Or provider poor readings? I'd contact B and G for guidance on offsetting it...

Let us know how you get on!!

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Re: Depth/Speed transducer location questions.

Post by prjacobs » Fri Dec 30, 2016 5:04 pm

Thanks for the link to your article .. excellent information, and Ballad specific too! I plan on using the DST800 transducer that is also a speed unit, so the hole has to go through the hull :( I'll check with B&G and see how much angle is allowable on the transponder.
Thanks for the info!

Bob McGovern
Joined:Fri Oct 26, 2012 3:08 am
Location:Wyoming, USA

Re: Depth/Speed transducer location questions.

Post by Bob McGovern » Mon Jan 02, 2017 5:45 pm

Our speed paddlewheel is under the port settee, just about center of the keel and fairly tight up against the bench face.


The depth transducer, less affected by turbulence, went thru on the stbd side, under the galley sink. I'm planning a combination speed/depth unit (probably a B&G) where the current paddlewheel is. The Ballad's sections there are reasonably flat, and if we are heeling enuf for it to mis-read by a foot or two & cause a grounding, we're probably carrying too much sail for that water depth! (I suspect most of time soundings become truly critical, you are motoring anyhow and therefore upright.)

Ballad may be flattest behind the keel, but that's a turbulent place. Farther forward you go, the cleaner the readings but hull angles become sharper. Due to the Ballad's construction in a 2-part mold, I'd worry a little about drilling thru the center seam too much. Also hard to get a good seal. Which sort leaves either side of the keel transition.

Joined:Mon Oct 20, 2014 6:35 pm

Re: Depth/Speed transducer location questions.

Post by Orion » Sun Feb 05, 2017 6:10 pm

My paddle wheel is located at dead center of the cabin floor access plate, just forward of the keel, as in your illustration, without a fairing as I thought this might cause a bit of turbulence. It had been mounted on the port side outboard and forward of the raw water intake. Installed a depth transducer, with a fairing block, at that location and moved the paddle wheel to the present location. Never gave any consideration to the structual integrity, center line, or hole as the thing is built like a tank. Is your new unit removable? Due to the rapid growth marine gunge mine is plugged except when in use.


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Re: Depth/Speed transducer location questions.

Post by prjacobs » Tue Feb 14, 2017 11:43 pm

I've put the instrument upgrade on hold for now. Between new roofs for the house & garage, and having a 'new' toy to play with, I'm going to enjoy the boat as it is for now.
One thing I will upgrade is to add wireless to my AIS/GPS system so that it'll send the info to my Android tablet in the cockpit with no wires to worry about. I found a neat little NMEA to WiFi bridge at YAKBITZ.COM, in Australia, and it's on it's way. Looking forward to getting it all connected as it will also work with my laptop.
OpenCPN has a good app that runs on Android with AIS capability, and I also have Memory Map Navigator as backup software.
Life just gets easier every day :-)jj

Joined:Tue Oct 23, 2012 11:51 am

Re: Depth/Speed transducer location questions.

Post by patentnick » Mon Feb 20, 2017 8:02 pm

Hi Peter:

I've mounted my Nasa depth transducer in the location you're indicating, slightly offset. Mind you, I've mounted it on the inside of the hull, not through the hull. Previously, the transducer was suspended in an oil bath (castor oil, I think), within a special tube, but I didn't like that arrangement too much. I took it out, cleaned it, smeared the head with Sikaflex 291 and positioned it on the inside of the hull. I slightly abraded that spot to make sure it was really clean and flat. When you choose in-hull mounting, you lose most of the greater depth range, i.e. it won't measure all the way to 100 or 200 metres. Mine shows up to about 40 metres but that's plenty for me.

As for a speed transducer, I don't have one since anything I've tried hasn't been accurate and fouls easily. I use the SOG on the GPS instead.

Nicholas Koligiannis
Moments of Clarity
Hull No. 334

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