Identify These Thru-hull Transducers?

[TRFrederick]

I need to find replacement retaining rings for these two plastic through-hull transducers. The threads are M42 x 2.0. Any ideas?

The backstory is that the battery exploded on our 1995 Hunter H23.5. It was on the trailer and the acid ran to the low point of the bilge where these transducers are located. When I found it there was a roughly 3/4" deep puddle of acid around the xdcrs. I don't know how long they were soaking, somewhere between a couple days and 4 weeks.

The rings were mostly corroded away as you can see in the photo. That really surprised me but it turns out that nylon has little resistance to sulfuric acid.

The 4200 was softened but the transducers are immovable and feel unaffected. I plan to scrape out all the soft 4200 and then soak in a puddle of baking soda-water solution for about a week. Then a clean water rinse and put it all back together with fresh 4200.

Thanks for your time!

 

[Apex]

yikes! Try Airmar. G/L

my question is the rest of the transducer now suspect as well?

 

[seadaddler]

5200

I would think 5200 because more better for under water and if I remember
when I changed my transducers the install paper work said to use 5200.
Well the newer Airmar transducers are different size than the older ones and had to make the hole larger maybe 1/8 but not sure.
I may have the left over old ones but they in Florida and I am in NY until Sept
but yes see what size you have and get in touch with airmar or hunt around
Marine traders where they sell old equipment and I did find some in one but they back home in Florida and not really sure what size they are or look E-Bay is good place to look or Craigslist for old equipment.
Nick

 

[TRFrederick]

I scraped all the softened 4200 out. (I assume 4200, it seems like 4200.) The softened stuff was in a layer about 3/16" thick. Under that it felt like good, solid, tough, rubbery well-cured 4200. After that soaks for a week in a saturated solution of baking soda I'm confident it will be OK.

In the process of scraping I worked around and along the transducers with a little screwdriver. I also ran the tip (with a spec of paper towel) along many threads to clean them out and also poked at them a few places. Everything felt solid and looks like new when cleaned up. I pushed and pulled on the xdcrs with quite a bit of force and again everything feels solid.

I emailed Airmar and we'll see what they have. If worst comes to worst and I can't get the threaded rings, I think I'll just put it all back together with 4200 under those starboard "washers" and hold down the washers with some wedges until it cures.

seaddaddler, regarding 5200 vs 4200, most of the info I've seen suggests using 5200 for non-removable applications and 4200 if you'll probably have to take it apart sometime. Considering these 20 year old xdcrs now may be getting toward a higher failure rate, I'm liking the 4200.

Interested in others' thoughts!

 

[jssailem]

The reading I've done says 5200 below the waterline. 4200 for hardware you may want to remove. I sense the 4200 below the waterline without solid compression hold downs is asking for trouble.