Depth Transducers Questions

[hughesw]

Questions - Are depth transducers from different manufacturers compatible and/or replaceable with other units?

Are there significant differences between transom-mount and in-hull transducers?

Is my problem in the wiring (connector) or in the location of the transducer?

Background - My CD-22 came with a Standard Horizon DS-35 Depth Sounder mounted on the port-side cockpit bulkhead. The transducer was mounted on the transom which, to my mind, was not very aesthetically pleasing and only seemed to be actually in the water when someone was sitting in the cockpit. But it at least worked.

I decided to move the transducer from the transom and mount it inside the hull, on the port-side just aft of the quarter berth in epoxy resin. (Yeah, I know, shoulda, coulda, woulda . . .) The area the transducer is mounted in is solid fiberglass and is relatively level. The epoxy was rather thin and there was no evidence of air bubbles. One thing is for sure, that transducer is not coming out of there without a fight.

In the process of pulling the transducer cable the RCA-type connector at the end of the cable became stuck and I ended up cutting the cable and soldering on a new conenctor. At first the only indication I got was "--.-". I checked the connector and the shield and conductor were making contact, so I re-soldered the connection, ensuring the two were not shorted together. Now the only indication I get is "11.5", regardless of the actual depth.

I went thru the all the steps of programming the unit but nothing seems to work properly.

I've searched for a replacement in-hull transducer (Standard Horizon DST-55) but it apparently is out of production and no longer available. I found one for $89.99 on one web site, but that's almost the cost of complete unit w/transducer.

[Neil Gordon]

>>Are depth transducers from different manufacturers compatible and/or replaceable with other units?<<

Sometimes yes, sometimes no. I replaced my Datamarine meter with a Standard Horizon one and tested the new meter with the old transducer. (A new one would be a different size, which escalates the project.) It's worked perfectly for about a decade. Without testing, you'll need a techie or tech support to tell you which work and which won't.

>>Are there significant differences between transom-mount and in-hull transducers?<<

You left out thru hull transducers.

Transom mounts work when they're in the water and vice versa. It wouldn't be my first choice on a sailboat.

Thru hulls mounting should give you the best performance, with the most difficult installation and yet another hole in your boat.

In hull installation had been mostly adequate. You may lose some maximum depth but that's not an issue unless generally. More important is to get a solid, level mounting.

>>Is my problem in the wiring (connector) or in the location of the transducer?<<

If you get a constant 11.5 reading, it's not the location.

Given the history of cutting the cable and repairing it twice with different results, I'd consider that the problem.

>>... and mount it inside the hull, ... in epoxy resin.<<

Ouch! It's lots easier to remove a transducer mounted in mineral oil.

>>I've searched for a replacement in-hull transducer (Standard Horizon DST-55) but it apparently is out of production and no longer available.<<

See if you can borrow a cable that hasn't been messed with for a test. If that cures the problem, see if you can buy just a replacement cable.

[seadawg]

I also had an old sounder system that I fought with for awhile and finally gave up on it and installed a new Raymarine ST 60+ with an Airmar P-79 in hull transducer. The transducer is mounted port side, forward edge of setee and just aft of sink. This transducer can accomodate a 22 degree hull deadrise which is just right for that location. It is necessary to cut approximately a 4" diameter hole through the liner to get to the actual hull. If you mounted your transducer aft of the setee I would think it would still be out of the water at times. Is there a liner at that location? The transducer will not work through the liner. Anyhow, the P-79 is working very well. Cheers. Charlie

[hughesw]

Looks like the Airmar P79 is compatible with the Standard Horizon unit I have.

When you cut out the section of liner, how much clearance was there between the liner and the hull? And, what sort of tool did you use to cut it out?

[Maine Sail]

I also have a Standard Horizon DS-35 and and I'm currently using it with the original 20+ year old Datamarine transducer.

In about 5 minutes I'm heading to the boat to install an ST-60 Depth and will again, but temporarily, be using the Datamarine transducer. It does work with the ST-60 and I've already tested it.. As long as the transducer is the right frequency, usually 200 not 210, (for Raymarine, Standard Horizon and some others) it should work.

When I get a chance I will be installing an Airmar in hull transducer as my Datamarine is currently "shoot through" and it's worked flawlessly for the last 20+ years.. The Airmar shoot through transducers are about $100.00+/-

When re-installing an RCA connector make sure the pin is going to pin and shield is going to shield. This can be checked easily with a resistance test using a multi-meter.. You can always cut and do a physical splice but those wires are teeny tiny and can break easily!!

[seadawg]

The P-79 comes in different flavers. With a little research you may find the version that has the connectors to match your unit. The clearance between the hull and the liner varies all over the boat. The transducer comes with very good installation instructions. Remember your boat may be different than mine. I mounted the P-79 under the port Setee forward bottom corner. Carefullly start with a very small drill...1/8" or so and drill through the liner only. Bend a piece of 1/16" wire to 90 degrees with a 2" radious. Insert it into the drilled hole and rotate it around. This is a feel inspection. Cape Dory spot bonded the liner to the hull at random locations and you don't want to deal with these welds. I used a 4" diameter hole saw from Lowes and a variable speed drill. Carful with the hole saw pilot. I also built a plywood partician to protect the P-79. Hope this helps. Cheers, Charlie