Hi Mark I can't offer advice on what electronics to buy, but can on enlarging the hole. I'd rather spend an hour poking myself in the eye with a pencil than trying to enlarge the hole with a dremel...
You will want a set of hole saws for this, and if you have both a 2" and a 2.25" hole saw there are a couple of possibilities: 1) if the center for the hole saws will allow you to mount two saws at a time, put the 2.25 on first and the 2" on second. This will let the 2" act as a center guide for the bigger saw. or 2) use the 2" saw to cut a hole in a piece of wood. The cut-out bit from the center is what you want, take that and glue it in the existing hole - hot melt glue will work, whatever you have available that will fill the gap. Then use the 2.25" saw, the hole in the center of the plug will act as your guide and keep it from wandering. cheers, Graham Collins Secret Plans C&C 35-III #11 On 2017-09-03 2:46 PM, Mark G via CnC-List wrote: I have the bottom of my 25 Mk1 down to bare gelcoat. I figured now is a good time to replace all the thru hulls including the old knotmeter and depth transducer. These have not been functional since I've owned the boat. I've gotten by with an old hand-held Garmin GPSmap 76. To be honest, I'm mainly just looking to plug the holes in the bottom. I managed to replace the old analog knotmeter with a combination of new and rebuilt parts. I'm now looking to replace the transducer. At some point the prior owner had a GPS or fishfinder mounted in the companionway because the bracket is still there. I'm looking to do something similar. I want a mounted GPS, and I want to be able to plug in the transducer for an actual depth measurement (rather than an approximate measurement from the electronic chart). And I'd like to do this for less than $500. I'm not looking to find shipwrecks or the last fish in the ocean, and I don't care about water temperature or what is 1000 feet below me. I just want to be able to anchor, avoid running aground, etc. At this point I think what I want is an obsolete Garmin GPSmap or Echomap 500 series, with an Airmar transducer. There's not much info online that's geared towards day sailors. Any advice or recommendations? Most thru-hull transducers seem to be 2.125 inches in diameter. The one I removed is 2.0. It's difficult to open up a 2.0 hole to 2.125 with a hole saw. Would you recommend grinding the hole larger with a Dremel? The transducer I removed was mounted in a wood fairing block. The deadrise angle seems to be about 10 degrees. I see that some of these transducers are internally gimbled up to 20 degrees. Is that the preferred approach for a sailboat considering the heeling angle on opposite tacks, etc.? Or should I just make another wood fairing block? Mark C&C 25 Dartmouth, MA _______________________________________________ This list is supported by the generous donations of our members. If you wish to make a contribution to offset our costs, please go to: https://www.paypal.me/stumurray All Contributions are greatly appreciated!
_______________________________________________ This list is supported by the generous donations of our members. If you wish to make a contribution to offset our costs, please go to: https://www.paypal.me/stumurray All Contributions are greatly appreciated!
