Hi gang, Last fall I wrote about removing my depth sounder as water was leaking in. It was a traditional external depth sounder with a mushroom head. It was held in place with a locking nut that screwed down against a wood backing block.
I dug out the rotten wood and ground down all the glass that had been used to hold it in place. The installation was really overkill. I wasn't able to remove the transducer without stripping the threads, so I bought a new one. I now have a smooth, pretty flat surface around the transducer hole. I bought the same transducer (Raymarine, i.e. Airmar,) So here are my questions: 1. I have made up a fibreglass backing block, but do I really need a backing block given that there really aren't any stresses on the transducer? It's not like a through-hull where you are opening and closing a valve. 2. The new transducer came with a rubber washer that sits on the inside and the locking nut is supposed to be hand tightened down onto it. Is this really a good idea? Won't the rubber shrink a bit with age? 3. For my sealant, is there any difference between 3M 4200 and Sikaflex 291 sealant/adhesive? I'm not sure if the Sikaflex is suitable for underwater applications. My current thought is to use the backing plate given that I've made it up already and skip rubber washer. Thanks, Mike Atacama. 33mkii Toronto 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!
