reposition depth finder without ruining transom

[capslock118]

see photos below.

I'd like to remove the screws and adhesive I used to bond the sonar mount to the transom, fill in the holes from the screws with 5200 or the like, then re-mount the sonar to a new location. (the gist of it is I was slightly off when I mounted it and the result is water spray on the engine cowl while underway.)

As you can see, the sonar is below the water line. So, I wouldn't want to remove the screws and fill it in if there is a risk of leakage which would, in turn, destroy the transom.

 

[H20Rat]

Re: reposition depth finder without ruining transom

Why not try just positioning it up a little higher first? From the pics it looks like you might have a little room to play with yet.

 

[Bondo]

Re: reposition depth finder without ruining transom

Ayuh,... Remove it, clean up the area, 'n fill it in with Marine-tex...

 

[Pez Vela]

Re: reposition depth finder without ruining transom

It appears that the transducer is mounted too low, and that would account for your complaint of excessive water spray. Among any number of possible solutions, one would be to simply raise the mounting height of the transducer without putting any more holes in your transom, and without having to seal the ones already there. I'd fashion a small mounting plate, just large enough to reposition the transducer's mounting bracket a little higher. After removing the transducer, I'd attach the mounting plate, utilizing the same screw holes that are already present. Then, I'd attach the clean transducer to the mounting plate, raised slightly from its former position, being careful not to penetrate the mounting plate and putting new holes in the transom.

 

[Hank496]

Re: reposition depth finder without ruining transom

Ayuh,... Remove it, clean up the area, 'n fill it in with Marine-tex...

+1, Or use generic epoxy such as West Systems etc.

 

[NYBo]

Re: reposition depth finder without ruining transom

Humminbird, I presume? Their transducers are notorious for the type of spray you're getting. The first step (after cleaning off the barnacles) is to raise it as far as the slotted holes let you and see what happens. There is also supposed to be a rubber piece that fills in the space between the transducer and the mount, but I don't know where to get one. Perhaps Humminbird's customer service could help.

 

[capslock118]

Re: reposition depth finder without ruining transom

Humminbird, I presume? Their transducers are notorious for the type of spray you're getting.

Yup. The instructions, as I intelligently took a closer read after the fact, stated that the transducer should be on the same plane as the bottom of the hull; not higher or lower.

Among any number of possible solutions, one would be to simply raise the mounting height of the transducer without putting any more holes in your transom, and without having to seal the ones already there.

Well, I misspoke. You see the two screws there, those allow the transducer to adjust in height without removing the screws. There is one on the bottom of the mount that does not have space for give, so If I move the transducer up I would still have to seal at least one hole.

 

[capslock118]

Re: reposition depth finder without ruining transom

Just to update this thread with a closing. I took the one screw out that keeps the mount in a permanent location. I found that in order to get the bottom of the transducer even with the bottom of the boat I had to remove all three screws; that's how low the transducer was mounted.

Now the hummingbird manual stated that I need to align the seam of the transducer (which is in the middle of the transducer top-to-bottom) with the bottom of the hull. Instead I made the bottom of the transducer even with the bottom of the hull.

The result was absolutely no spray even at top speed of 40mph!

I used marine tex to fill the old screw holes, sanded then drilled new holes; sealed the screws and mount with 3M fast cure 4200; finished the work with a coat of bottom paint.

 

[cr2k]

Re: reposition depth finder without ruining transom

If you aligned the transducer with the bottom of the hull you are now looking sideways. (where you are NOT) The transducer needs to be level to the water surface to look straight down. (where you ARE)

 

[capslock118]

Re: reposition depth finder without ruining transom

Hi cr2k,

I should have been more clear. Look at the photos I posted in my OP; just imagine my transducer mounted in the exact same fashion just 5 inches higher than that.

 

[cr2k]

Re: reposition depth finder without ruining transom

5" looks like it would put it out of the water. But the alignment would be right. Wasn't quite sure.

 

[capslock118]

Re: reposition depth finder without ruining transom

5" looks like it would put it out of the water.

Yeah i'm really just estimating here; it's definitely in the water - maybe not on plane but I don't care about depth when cruising. It could be 5", it could be 3" - I didn't really measure - I just made sure that the flat bottom of the transducer is straight with the bottom of the hull using a straight edge.