Depthsounder Transducers

[Stu Jackson]

Three parts to the depthsounder

1.  Instrument display - going MSD on and off, more off than on -- can remove the electronic module and have DMI check it out
2.  Wiring - will check it and connections
3.  Transducer - under V berth easily accessible from a drawer we installed years ago, low, like Ron Hill's November 2006 Tech Notes article

Question:

anyone left the old transducer and installed one WITHOUT replacing the old thru hull transducer, and just "gluing" it to the hull with, say, toilet wax ring material?  Like: http://www.catalina-capri-25s.org/forum/topic.asp?TOPIC_ID=14159

[Ron Hill]

Stu : I had a friend that swore by his "inside the hull" transducer.  He held it in place with modeling clay.
Just watch out for the parallax.   

[Gary]

Stu,

We have Datamarine Instruments (1986 vintage) and they are still going strong, with some help.  We did need to replace the speed paddle wheel transducer.  Apparently, over time, moisture wicks along the cable and effects the receiver processing in the paddle wheel.  The good thing is that a new transducerstill fits the old Thru-hull so there is no need to replace anything but the transducer. That makes a mid summer repair nice and easy...no haul out required.

To determine if the instrument or the transducer is at fault the test is to use a paper clip at the instrument to bridge the contacts at the point where the transducer plugs in.  If you pulse the paper clip it simulates current from the paddle wheel and you can check the instrument for a speed reading.  If you show a speed reading on a problematic instrument than the transducer is the fault.

Datamariine is terrific on the phone helping with diagnostics and they still rebuild as well as have owner exchange for new programs.

Hope this is helpful.

Gary

[Gary]

Stu,

Sorry for missing that your concerns were with depth not speed transducers.  A senior moment?

Anyway, hope the info on Datamarine's great service and diagnosing a failing speed transducer is helpful to all.

Gary

[tonywright]

Stu

I once had a C&C 24 with a transducer installed the way you describe. Apparently it is important to make the transducer feel that it that it is immersed in liquid. The PO had used a section of PVC drainpipe, shaped to the hull and epoxied, and topped with a screw-in cleanout cap to contain the transducer. The wiring was fed through a hole in the cap that was sealed. The pipe was filled with "baby oil" to create the liquid environment.  It seemed to work for depths up to about 100ft, but I had the check and top up the baby oil every season!

On the other hand, on my next boat, I had the original transducer removed and replaced with an ST60 kit. This seemed to be a very simple procedure. Much easier than I had assumed.

[Ken Heyman]

My DataMarine transducer failed the first season after the purchase of our 1988 C34. Since then (four seasons), I have been quite happy with my Piranha fish finder(aprox. 70.00) display brought into the cockpit. It is positioned by the port bulkhead and is easily visible from the helm. As this was originally supposed to be a temporary fix, I placed the transducer next to the thru hull for the knot meter(just forward of the mast by the starboard bulk head). If I mount it permanently, I will probably suspend it in a jar of mineral oil (recommended by surveyor) and use and adhesive such as 4200 around the lip of the jar to attach to the fiberglass surface. The jar is inverted and a hole drilled for the wire. That said it works perfectly simply weighted down. No thru hull is necessary as fiberglass is evidently a great conduit for sonar. There just can't be any air bubbles between the transducer surface and the fiberglass.

Ken

[Stu Jackson]

Ken

I've reread your answer a few times and still can't find the method you used to temporarily install the fish finder transducer.  What did you use?

[Ken Heyman]

Stu,

Hope the following helps:

I connected the power supply for the fishfinder directly to the battery via a fused connector.I remove the fuse when not using the fishfinder i.e. not cruising my home waters where all is familiar etc.

I applied a bit of vaseline to the surface of the transducer and placed it (accessing via the panel behind the v-birth bulkhead - that is closest to the centerline of the boat - if you were sitting atop it you would be facing aft looking out the companion way) just forward and slightly to the right of the mast(when looking forward) on the lowest flatest hull surface possible. (on my boat this is right by the thru hull for the knot meter impeller).  I moved it around and watched the display on the fish finder to make sure it was in a good spot and was getting a reading.   I then weighted it down and voila----all set on a temporary basis.I lead the wires aft through the bilge. I get depth, fish and temperature all for about $70.00. I bring the display unit into the cockpit for access and visibility.
The two wires (transducer and power) are led under a  carpet and behind the  ladder to keep them out of the way. When not using the unit I coil the wires and put them in to battery compartment. ---not terribly professional but highly functional.


The best way to install the transducer permanently  is what was described by Tony using PVC. That is similar to what I attempted to describe  was suggested by my surveyor and what I had done in my C27.

Sorry for the confusion.(hope I didn't create more)

Ken

[Terry Forshier]

My original transducer is located in the back of the boat behind the motor under the aft berth. It has a tendency to lose the sounding and go blank just when I need it. I had a second depth sounder (a Uniden) with a shoot through the hull transducer. I mounted the transducer forward in the boat under the port seat in the cabin. I just glued the transducer to the bottom. (first I sanded smooth the fiberglass area that the transducer would adhere to) then glued it to the hull with the glue provided by Uniden. I ran the cable back through the boat to the cockpit where I mounted the display and an on/ off switch. It has a setting on it that one can control the sensitivity.
Now when one is off the other usually is reading. So far this has worked well for me.
I have also put a transducer (through Hull, no hole) on my fishing boat. I USED A ds41 system from Standard Horizon. It sits in a little cup of mineral oil that is glued to the bottom of the inside of the hull. This also has settings for sensitivity. It works well. There is no noticable difference in the quality of the two.

[Jim Price]

I have an older Humminbird SX100 the PO installed similar to what Terry did using the provided Hummingbird "shoot through the hull" transducer.  I has worked great for many years now.

My only addition is that the transducer is located WELL forward under the V-Berth and it has saved my butt sever times already this year with the water level down in Lake Lanier.  Being forward allows me to see "what's coming"  when in marginal areas - and I have a fully loaded boat with deep fin - so I get real squirrelly when the fish finder starts showing any thing below 10 feet.  Still gives me time to maneuver out of the area.  Also shows stuff like sunken concrete pier anchors in the marinas that were never an issue before when water was deep.  Hurts if you hit one of those!!

All cables run under sole to pedestal and up through pedestal to unit mounted on guard.  Power is shared with Instruments breaker at panel.

[Stu Jackson]

Thanks to all of you for your ideas.  Here's some more...

1.  Terry, welcome back, great to hear from you, and thanks for the input.

2.  Ken wrote me this: "I secured the transducer with an old bag of lead shot( my Dad used to reload his 12 gage cartridges for skeet shooting---a very frugal guy). I stumbled upon the bag at my Mom's apartment and decided to use it as a field expedient. Anything relatively  heavy and a bit malleable will work, I would guess. Again the best method is what Tony described.  I should note that occasionally the transducer may stop talking to the fish finder. I have corrected that by simply dumping a cup of water onto the transducer. This takes care of the air bubbles and she is fine."

3.  It's interesting that so many of you have found "ways around" and with new equipment.

4.  Jim, there was an interesting thread on www.catalinowners.com about sailing on Lake Lanier for a C30 potentially moving there who was concerned about the depths.  I mentioned your C34 Fleet 13 there.  Sounds like you've got it covered.  Hi to Dottie and the rest of the crew.  Keep up the good work and wine parties!!!  :

I haven't decided what to do, yet, it's still behaving as originally posted.  The one thing I haven't done yet is to just give it a kick!

[Hawk]

Reading this old thread I'm looking at replacing the depth sounder and possibly speed. The original Signet display is shot.
Furuno has an RD 30 display and single transducer with depth, speed and temp.
Has anyone had experience with Furuno depth sounders?

Many thanks,
Hawk

[Craig Illman]

Tom - I'd really consider a NMEA0183 or NMEA2000 transducer and then you could use any NMEA0183/2000 repeater for a display.

Just to muddy your waters......

Craig

[Hawk]

Craig,
Looks like most transducers, Raymarine/Furuno are available in NMEA 183 and 2000. I suppose either will work equally well.

[Hawk]

Turns out I did a little repair on the knot meter transducer to get it spinning and sent my 20 yr old Signet depth/knot display down to Signet Marine in California. What a great experience...they fully tested and repaired the unit, replaced the screen, face plate and buttons. Just plugged it back in and its like new using the original transducers.

Anyone with Signet equipment issues shouldn't hesitate to give them a call.
http://www.signetmarine.com/

Hawk