transducer upgrade

[gray duck]

Sometimes obstacles can be stepping stones... That's what my pastor said a couple of weekends ago. Hoping it is true. I put my 2520 on a new lift for the first time and got itr wrong by two inches and put the transducer between bunk and boat. Ouch! So it looked like the fairing block was cracked and I knew I needed to change that out and reseal at a minimum. After pondering awhile I decided to go with 1 kw airmar flushmount. That requires a 3 and 3/4" hole! :shock: Getting the old one out was tough - frozen bronze in tight bilge with small hatch etc etc

inside

Wrench didn't work so enter Capt Dremel

After that it came out pretty easy so I'm thinking they didn't use 5200. Thank you!
Here's my new solar powered underwater fishlight

 

[warthog5]

When it's time to drill the bigger hole for the tilted element unit.

I'm guessing you have a 2in hole in the boat now? What ever it is.....Use that size holesaw and cut a disc out of 1/2in or 3/4in plywood. Leave the tape you have there. Use 5min epoxy [I add some cabisol] to it to thicken it and glue the disc in the hole.......Now you have a center point for the 3 3/4in hole.

 

[gray duck]

The reason I hope this is a good thing (a stepping stone not an obstacle) is that sometimes coming in with a following sea the port engine would wind up (RPMs to 50s) secondary to cavitation. I'm hoping that it was secondary to the larger transducer directly in front of it. Any votes for what type of sealant I should use? 5200, 4200, lifecaulk, ???? thanks

 

[gray duck]

I poured thickened west system epoxy onto the wax paper and tape yesterday so the hull is sound and leak proof just incase Murphy comes around. Hopefully I can drill hole next weekend. Little nervous about that one...

Here's a shot of the new ducer. Pic doesnt really do it justice - thing is a brutte - like 8 or 10 lbs

 

[bean]

Use 4200 Not 5200 if it ever goes bad you can get it out.

" Bean "

 

[warthog5]

Use 4200 Not 5200 if it ever goes bad you can get it out.

" Bean "

X-2........... And Stop steeling Momma's eggs.

That appendage can surly affect a motor that is behind it.

 

[DaleH]

FWIW it will come out with 5200 on it too ... albeit a bit more work, but 5200 on anything threaded is not the magical elixir many would have you believe it is. I even removed an OB bracket 'glued' on with 5200 ... came right off with Anti-Bond 2015 product.

 

[Megabyte]

subscribed!

 

[gray duck]

update notes:
Determine location inside and drill pilot hole

Take large nerve pill, large drill, and large (3 3/4") hole saw

Wow! That's some daylight

 

[gray duck]

So with hole cut I'm in my dinghy under the boat with the adrenalin shakes. Now began the hard work of fitting. The inside is not exactly flat so the thick plastic spacer-donut had to be contoured so it would sit flat. So I began the trial and file - ie dry fitting from hell. I got the spacer so it could not rock back and forth over the hole and put the whole thing together. By the way - very hard for me to tighten the nut (4 1/4" span) and hold the transducer still by holding the two little tabs cut in the top - span of 2.2". I used lg stuffing box wrench but this is the one weak link in the ducer: not enough area to get decent grab. Read this as MCF - Major Cussing Factor. It was not a true fit - meaning I could get a credit card under one edge and the two rubber washers would not get tight all the way around. So now I have the spacer contoured but not a perfect fit. What is going on????



Hull thickness disparity! Boy did I feel stupid for not looking at that cut out sooner!!! So the grinder came out and the bilge quickly filled up with FG dust and a perfect fit:


Felt good at this point but the 4200 is about to hit the fan...

 

[Megabyte]

Hull thickness disparity!

Solid, hand-layed fiberglass. Gotta love it.
The 4200 will seal it, but don't crank down on that nut just yet.
Go 80 or 90%, let it cure, then give it an extra bump.
If you crank it down too far while the sealer is wet, it'll spit out the sealer and you'll have a dry joint.

 

[warthog5]

The inside is not exactly flat

That is where I take my air grinder w/ 7in 36gt disc and grind the inside....I've done a BUNCH that way.

 

[gray duck]

Your right. I sanded it smooth but my mistake was not grinding it right in the beginning because that was the key. For someone doing this my advice would be to use calipers to get the hull thickness perfectly uniform after cutting the hole. And airmar should make bigger tabs at top of ducer to grab on to.

 

[gray duck]

Finally an update...

She floats!

And the bilge is dry!

And we have a picture and water temp. Hopefully I'll have some images of some big schools of fish offshore to share in coming months. It hadvery clear images at full speed and the boat speed actually seemed a little better without the bulky external ducer but I know I may be just dreaming on that one...

All in all I'm happy I did it and I could definitely do it faster next time. One question I have is should I paint the bronze as the directions state (water based antifouling) or leave it alone since it is kept on a lift?

 

[warthog5]

Kept on a lift.......I wouldn't paint it.

 

[Megabyte]

Kept on a lift.......I wouldn't paint it.

I agree...
But if you must, use transducer paint.