Many systems have a thru-hull that the transducer and/or speed wheel fit inside. The electronic pieces can be removed and replaced without disturbing the thru-hull seal. Many even come with dummy plugs. Water tightness is achieved with a series of o-rings that should be lightly lubricated on occasion. The electronics and the dummys are secured by a pin and ring. You can remove the speed wheel periodically while in the water for cleaning. It only causes a little anxiety seeing a 1.5" column of water entering your boat. Over time you create a system and get quick to minimize the amount of water that gets in. I use a hand towel which balloons over the fountain of water and still gives be room to pull the transducer/speedwheel and then reinstall the plug. With a plug installed I use a tooth brush and the puddle of water in the bilge to clean the wheel. Once clean and getting a good signal to the instruments I reverse the process.
While on the hard you should be able to remove the electronics and with a small saw cut the thru-hull into sections. They'll be easier to remove/pry out. You should contact the manufacturer for a replacement thru-hull prior to starting. Don't use plywood as a backer. Use 1/2" G10 FRP and make sure to contour it to the curvature of the hull. Dry fit and then glue it in place with thickened epoxy. Clamp tight! Come back in a day and bed your new thru-hull with 5200. Here are some links to help. http://www.pbase.com/mainecruising/installing_a_thruhull http://www.pbase.com/mainecruising/backing_blocks http://www.pbase.com/mainecruising/replacing_thruhulls Josh Muckley S/V Sea Hawk 1989 C&C 37+ Solomons, MD On Oct 26, 2016 11:25 AM, "Michael Crombie via CnC-List" < [email protected]> wrote: > Thanks for the tips and info Dave...you clearly know a lot more about this > than I do! > > You are right, everything is plastic. As far as I understand it, no > matter what I end up doing, I need to get the backing nut off, get the wet > rotten plywood off, and get the sender out. Yes, I concur that I would > like to start with clean fresh surfaces. > > > My confusion is when you refer to a through hull fitting and the sender > separately. I had thought that the sending unit was essentially the > through hull fitting. > > My understanding of the process is: once I get the backing nut off and > all of the plywood backing plate off, I would next need to go under the > boat and slide some wire underneath the mushroom head fitting to cut any > sealant. Then I need to go back inside and grip the sending unit (where it > is not threaded) and try and rotate it to break it free of sealant. Then I > would clean everything, make a new backing plate, and remount. Is all of > this correct? > > Of course, if this doesn't work and I can't break things free without > destroying them, then I suppose I just need to do whatever it takes to get > everything out. Then buy a new sender with hopefully the same diameter. > Again, is this correct? > > Thanks again, > > Mike > Sent wirelessly from my BlackBerry device on the Bell network. > Envoyé sans fil par mon terminal mobile BlackBerry sur le réseau de Bell. > _______________________________________________ > > 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!
