I have an Oday 25 that I'm looking to install a nav/gps/depth finder unit on. I did a test yesterday trying to shoot the transducer through the hull. I did the test under the cockpit, between the transom and the keel. The cable is not long enough to reach the forward side of the keel. I've been told the way to do a test is to get a sounding next to the boat and then inside the boat against the hull with the transducer inside a bag of water. In a little over 4' of water I kept getting 6'. If I thought the difference was consistent I think I could live with the issue, and since her motor is off being repaired I can't do a test in deeper water. My next reluctant thought is run the cable over the transom, fabricated a fixture that will come off the lower rudder mount and have the transducer in the water. Any suggestions on how others have achieved this is greatly appreciated. kent
transducer through hull
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Thank you Chief, I'll try silicone next. If my test with the bag of water worked I was going to go with Expoxy but I like the idea of being able to replace it easier than ripping out epoxy. Do you have to work the silicone to get any air out? In the meantime I'm doing soundings through the hull at different tides to see if there's a consistent correlation int the difference. So I'm guessing you've not heard of anyone using the bag of water to test? Not sure why it would not work. Thanks again
I had a Catalina that I added instrumentation to. I epoxied the transducer to the inside of the hull and it worked fine. Build a dike of putty around the area to set the transducer, pour in the epoxy then place the transducer in the epoxy gently and twist it around to get any air out. Need a new one in the future just add one next to it!
John, I have an O'Day 23 and had the same problem deciding how to mount a depth gauge sensor. I did not want to do a thru-hole and like you I read a number of postings and was about to try the water in a bag technique when I saw another approach. Not sure where I heard/read this but this is what I did.
Decided on the location of the sensor - I chose a place in the bow just ahead of the keel. There is easy access under the forward berths.
Got some duck caulk from home depot or lowes. See link below
Cleaned the area where I was going to locate the sensor with some alcohol to remove any crud or other dirt.
Molded a handful of this stuff to soften it.
Took the sensor and put this softened lump it onto the end of the sensor.
Pushed this sensor with caulk onto the inside of the hull at the location I had chosen.
Tried to keep the sensor vertical so as to get the best reading.
Pushed down hard enough to push the sensor into the caulk but not so hard as to squish all of it out.
Hard enough to make it stick in position.
Molded the excess to provide support for the sensor. Yes it took a couple of trials to get it the way I wanted but it worked well and kept the sensor securely located on the hull.
Provided a strain relief for the wire on the closest vertical surface so that the wire was not bouncing about. Didn't think of it at the time but could probably have used the same caulk and just embedded it.
I checked the depth at my mooring and at a couple of other places and it was close enough for me. The depth sensor I used had a zero offset so I could get true depth depending on the location.
I chose not to do this since my boat draws 2 1/2 feet with the centre-board up and if I'm sailing in water with less than 2 feet .... well
Having said all that I will acknowledge that I have run aground 2 times ...... all within 200 yards of my mooring and both times on the edge of the channel as I moved to the side to provide room for a passing boat. I learned the hard way that the edge of the channel is the edge of the channel and it moves around a bit after storms etc etc.
How well has it worked .... Well it was done a few years ago - cannot remember when but I did not launch my boat last year so it sat on the trailer all year.
I splashed this year and it works great. My point here is that I have not had to fiddle with it since I put it in ..... But if I wanted to relocate or check something or who knows - maybe paint the inside of the hull ????? I know all I have to do is just pull it off and the caulk will be easy to remove.
Here is a link to the stuff I used.
http://www.homedepot.com/p/Gardner-...s-10-Pack-DS-110/100212441?keyword=duct+putty
Hope this helps. It was easy and very low cost and has worked well.
James
Decided on the location of the sensor - I chose a place in the bow just ahead of the keel. There is easy access under the forward berths.
Got some duck caulk from home depot or lowes. See link below
Cleaned the area where I was going to locate the sensor with some alcohol to remove any crud or other dirt.
Molded a handful of this stuff to soften it.
Took the sensor and put this softened lump it onto the end of the sensor.
Pushed this sensor with caulk onto the inside of the hull at the location I had chosen.
Tried to keep the sensor vertical so as to get the best reading.
Pushed down hard enough to push the sensor into the caulk but not so hard as to squish all of it out.
Hard enough to make it stick in position.
Molded the excess to provide support for the sensor. Yes it took a couple of trials to get it the way I wanted but it worked well and kept the sensor securely located on the hull.
Provided a strain relief for the wire on the closest vertical surface so that the wire was not bouncing about. Didn't think of it at the time but could probably have used the same caulk and just embedded it.
I checked the depth at my mooring and at a couple of other places and it was close enough for me. The depth sensor I used had a zero offset so I could get true depth depending on the location.
I chose not to do this since my boat draws 2 1/2 feet with the centre-board up and if I'm sailing in water with less than 2 feet .... well
Having said all that I will acknowledge that I have run aground 2 times ...... all within 200 yards of my mooring and both times on the edge of the channel as I moved to the side to provide room for a passing boat. I learned the hard way that the edge of the channel is the edge of the channel and it moves around a bit after storms etc etc.
How well has it worked .... Well it was done a few years ago - cannot remember when but I did not launch my boat last year so it sat on the trailer all year.
I splashed this year and it works great. My point here is that I have not had to fiddle with it since I put it in ..... But if I wanted to relocate or check something or who knows - maybe paint the inside of the hull ????? I know all I have to do is just pull it off and the caulk will be easy to remove.
Here is a link to the stuff I used.
http://www.homedepot.com/p/Gardner-...s-10-Pack-DS-110/100212441?keyword=duct+putty
Hope this helps. It was easy and very low cost and has worked well.
James
Hey James, I've been a home repair kind of guy for the better part of 30 years, know lowes like the back of my hand but I've never even heard of this stuff. This sounds perfect. Did you feel that you had to work air out of the product as you were working it? Or just worked it to soften? Very interesting how many different ways people have approached this task, from toilet wax to bees wax to mineral oil. Thank you
John I don't think it dries out.
I'll check the next time I'm on the boat. I know the stuff which is in my tool box/garage is still pliable but it is in a baggie.
the first year I put it in I played with it a lot making sure it was still OK - pulled it out a couple of times and re-bedded it and had no trouble then.
Since it worked the first time I turned it on I said "OK its working - scratch that off the check list- whats next." and moved onto the next thing on my list that needed checking.
The specs at the Home Depot link I posted earlier say it remains flexible and is rated from -20F to 350F and states ..... "Under normal conditions the material will not harden or form a skin"
I'll post a reply if I get to the boat in the next day or so.
The other caulk which could be used which I know stays soft is the stuff electricians use to seal the service wire where it enters the meter box where it comes into the house. When I had my service upgraded to 200 amps they dropped a new line to the meter. The ferrule type nut on the feed is sealed with a grey'ish caulk which looks almost identical to the duct chalk.
James
An electrician friend who I've been sharing this thread with said the exact same thing. Thanks for the solution.
James… rock solid idea! It works great, barely a 5" discrepancy now. I epoxied a piece of 4" pvc in place just to give the compound/transponder a home, and added a cap to protect everything from taking an accidental hit. Thank you very much.
kent
kent
Not having the same luck, but I wonder if its the transducer. I have an inexpensive fish finder that I thought would be fun for the kids, but I can't get it to give an accurate reading. When I hold it overboard it works great, but not shooting through the hull, although it says it should in the specs. I tried forward and aft, no luck, with both wax and a baggie.
James, I wonder if the inside of your hull is painted? Mine is.
James, I wonder if the inside of your hull is painted? Mine is.
Before you give up, try the stuff that James suggested, for a little over $2, you don't have much to lose. http://www.homedepot.com/p/Gardner-B...ord=duct+putty
Will do, but I'll put it on the spring list,. With only a few weeks of sailing left, little time at the boat will be spent doing projects.
Thanks for the tip!
Thanks for the tip!
Indy sailor, about the paint.... Yes the inside of the hull is painted. If it works when you hang it over the side I think it should work if you get a solid connection with the hull.
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