replace / remove thru hull transducer

[BarryL]

Hello,My boat (1986 Newport 28) came with two thru-hull mountedtransducers, one for speed, another for depth. I plan onremoving the existing depth gauge and replacing with a fishinder / chartplotter. Should I install a new transducer in the old transducersspot (any idea if it will fit?), leave the existing transduceralone and install an in-hull new one, or remove the existingthru-hull, close up the hole, and install an in-hull transducer?What about the speed transducer? Should I remove it and close upthe hole or leave it alone? I don't really like the idea of extra holes in the boat. I have not done much fiberglass work,is this something I can do myself? I have seen some instructionson a WestMarine site. If not, any idea what a yard would chargeto fix the two holes?In case anyone is interested, I plan on buying the Garmin GPSMAP 178Sounder. Mapping GPS, 4.5" mono screen w/320 X 320 dpi, plus a fishfinder.All for less than $400! I already have a small handheld garmin GPS,a Etrex Legend and Mapsource, so that will work too.Thanks,Barry

 

[Terry Cox]

Barry, I just finished installing the Garmin...

178C on our boat and in the process discovered a number of things to consider. The sonar transducer maker that Garmin uses (Call their support line, they will know who the maker is.) operates at either 200 (wide cone)or 50 (narrow cone) kilohertz. The Autohelm (Raymarine) depth transducer that came with our boat also operates at 200 kilohertz. I talked to the transducer maker and they told me to operate one or the other, not both, to avoid signal conflict. More than likely your existing transducer was made by the same company as your new one, just as in our case. They can tell you whether it will fit in the existing hole.Our new sonar transducer is the shoot-through transducer type, so no holes are necessary. I plan on turning off our original depth transducer, but leave it installed.Terry

 

[Bilge-Rat]

Speedo

As for the speed transducer (paddle wheel), just leave it in place unless it's leaking. You or the next owner may want to hook it back up some day. But they do have a tendancy to go bad after several years. No fuss, no mess. and Ditto on Terry's post.Fair Winds ~~~~~

 

[Scott]

Replaced Transducers

Hi Barry,I was in the same boat last summer. I replaced both depth and speed ... both Datamarine (paddlewheel for speed). Transducers were $100 each and I also bought the plug for $10. The only reason the instruments didn't work properly was because of the damaged transducers, so I didn't want to just waste them. The depth now works perfectly, the speed works nicely but needs calibration, but I'm on a small lake so what's the diff.I think transducers are damaged by lifting the boat with slings, so for haulout, I put the plug in one hole, the old depth transducer in the other. They never leaked and they have a smooth surface, so I wouldn't close the holes regardless if I want to use the instruments or not. Scott

 

[Ron]

hey scott

I have the same set up. Where did you get the plug from and how easy is it to switch the plug for transducer while the boat is the water.

 

[Scott]

Call Datamarine

I followed their links to service and repairs, got their phone # in Pocasset, MA and talked to a fellow named Tom. He was helpful and will sell you the plug ($10 per). I also bought the owner's manual since it wasn't on the boat when I got it. They send it to you right away and bill your credit card. Didn't have a shipping charge.At first, I was nevous about pulling the transducers while in the water. Have the plug handy, pull out the pin - the pressure isn't great enough to pop the transducer so don't worry. Wiggle the transducer out and pop in the plug. A little water comes in but just mop it up. The plug has a hole for the pin to slide through and your done! The plug comes with a little rubber o-ring to seal it in (just like the transducer)

 

[John Nantz]

Paddle Wheel Transducer Install Tip

When replaceing the speed transducer with the boat in the water be careful not get over anxious - the paddle wheel axel is quite small and it is easy to bend it by hitting the paddle wheel on the thru hull.With regard to your questions, if it were my boat, I'd install the new transducer in the same place as the old one, assuming this is a good spot. Most likely a different size hole will be needed - if the new thru hull is larger I'd remove the old one and epoxy a wood plug of some type in the hole. This the wood will provide something for the pilot drill of the hole saw to center on. The harder the wood the better. Seal the raw fiberglass with epoxy to help keep water out.If a smaller hole is needed then fill the hole with epoxy as needed. This has the potential for being a messy job depending on how much hole reduction is requied. A cardboard cylinder the size of the new thru hull might be handy.Can you do it yourself? Can't answer that because I don't know your capabilities but it could be a DYI project. When working with epoxy you need the proper proportions.

 

[jmcclain]

Transducers!

Barry,Most popular transducers are actually made by Airmar. From the information and crosss references on the Airmar website you can usually determine which transducer and thru-hull you now have. It will be fairly easy to determine whether the new transducer will work in your existing holes. IMHO I would not bother replacing the speed 'ducer. The GPS will provide you with SOG info.