Mounting a FF on my Tarpon 120

So you still have to add water with the putty method? Looks messy.

The other issue with the putty is when you transport you kayak and it's hot out. The putty will release from the plastic. it's a problem if you transport the kayak upside.

I have use RV putty in the past.

willbd

Hrm, I always transport upside down.  I may go back to the foam puck method.  I really liked the epoxy method, but you never know when you're going to want to move something.

I decided that Im going use the water-in-foam-puck approach and just refrain from capsizing.

If I chose to go with the transducer arm, then I would still have to run my power wire into the hold. Now I think that I'd rather do the foam puck and thus avoid having another mechanical contraption on deck. It will be a tall puck, standing proud inside the hold!

It shouldn't be that hard to make a "male" foam cap that fits snugly down inside the inner rim of the foam puck.  To insure a good seal, one could put some putty around the edges, as well as in the small slit the transducer cable goes thru. I'll try to make the cap a good fit, so I won't have to mess with any putty.

I ended up mounting my transducer down with marine silicone and at this point it still works great.  I'm not sure if heat will affect it but if it does I can always just peel the silicone try again.

So you still have to add water with the putty method? Looks messy.

Yes I hate it when I get water on my kayak

So you still have to add water with the putty method? Looks messy.

Yes I hate it when I get water on my kayak

On is okay, in I do not like

On my Pungo I made a plastic holder that is glued to the kayak behind the seat.

On my Pungo I made a plastic holder that is glued to the kayak behind the seat.

I see the wire retainer and understand you fill with water, but what holds the transducer tight to the bottom of the hull?

It's own wight and the shape of the cup.
I took this photo with the kayak hanging upside down. 

Got home yesterday evening and found a package on my porch... Yeeha! My Lowrance Mark 4 DSI sonar/gps finally arrived!

Hmmm, going to need some in-line fuses, and some kind of battery box or mounting bracket for my Cabela's sealed rechargeable 12 volt.

The Mark 4 DSI has a strange torpedo-shaped transducer, that is rounded on the bottom and over 3" long. I am going to have to be very observant and careful when installing this, so that it is oriented correctly and sends straight down.

The transducer on my older sonar is flat on the bottom, so that one was pretty easy. This new torpedo shape is going to be more difficult.

So you still have to add water with the putty method? Looks messy.

I've heard, no need for water, which is why I want to try.  I've used a foam reservoir and water and it worked well, but needed refilling.  Then I used the foam reservoir and marine grease, and it worked well until it didn't and I'm not entirely sure why.   Could be air got under/into the grease.  I've tried resetting it, but no joy.

My current plan is to clean out the grease from the foam reservoir.
Make a 1/2" (or so) thick oversize pancake of putty on a board on wax paper outside the kayak, and press the transducer into it.  Cut the pancake so it will fit in the cleaned out puck, peel off the wax paper, and install in the foam reservoir.

I'd like to keep the foam reservoir so I can go back to water if I need.  If I can't make the putty work with the foam, I'll just rip out the foam and try it on the bare bottom of the yak. 

I thought he used water in the putty mount on the video?

I think the only way to go without water is to goop or epoxy straight to the hull.

I thought he used water in the putty mount on the video?

I think the only way to go without water is to goop or epoxy straight to the hull.

What's the difference between putty, goop, and epoxy, except an increasing spectrum of permanency?  They are all sticky and attach the transducer to the inside surface of the hull.  If you don't need water with goop or epoxy why would putty need it?  We are simply looking for a seamless acoustic coupler that will stick to both the hull and the transducer.  I'll bet that silicone seal would work as well and I am surprised no one has reported trying it. 

In the video, he made a 'well' with the putty, he didn't use it like a glue, which is how you would use epoxy or goop. 

As for silicone, I used a marine grade silicone adhesive to attach my first foam puck.  It peeled right off with little effort.