depth sounder

[david g]

has anyone replaced the original thru hull transducer on a 28? what size is the hole?how hard is it to remove the old transducer?all answers &comments will be welcomed. thanks

[Paul D.]

i just did this job on our 33. I think your hole size will depend on the actual transducer brand and model. Mine was an old Signet depth. I had a rather deep transducer that stuck out of the fairing block a good two inches. The new one is flush with the block. One reason I went with the Raymarine was because someone on the board suggested the hole size would be the same. That was true for the speedo, for which I only needed to build up some epoxy along the rim of the hole as the old transducer was flush, leaving a concave bevel. Here is the old speedo hole before filling the bevel with epoxy.



Here is the old sounder hole after removing the through hull and teak fairing block.


The old hole was about 1 1/2" and the new one, for a Raymarine St60+ was to be two inches. I needed a deep 2" hole saw. I drilled the hole, sanded the area for a new fairing block and dry fitted the new one and then sealed with 4200. Here is the new sounder transducer and the speedo below.



Be sure to give yourself extra time for this job in case you need to do multiple epoxy build ups. I didn't need multiple layups but I didn't expect to fill the speedo hole, I probably could have gotten away with not filling it but a little voice in the back of my head told me to do it right. Don't forget to map out the wire runs too, if you have a wheel and binnacle check to see how much room you have for wires to go up the pedestal. Mine just fit through a PVC tube when I pulled through the old wires. I can add no more electronics there!



She's in the water now and all is good. This weekend will be the test when I get back up to the boat.