Transducer Mounting Suggestions

[southkogs]

I'm catching up on some "to-do" items today, and one of them was mounting the Hummingbird Helix I got for the boat. Didn't really have a plan to get one, and don't do a lot of fishing where I need a finder, but the other functions are going to be something I use a lot (depth and plotter) and it was an easy grab!

I was going to mount it today, but ran into a bit of a snag that I'd like some advice on before I make a decision. The transducer is supposed to be at least 15" away from the drive, and of course it needs to be in the water. According to the install instructions, if it's in the water at planing speed you'll still get a reading. That's not an absolute must, but I like the idea (again for depth). Here's my jam up (see image):


To the starboard of the outdrive, 15" away falls right on the outboard lifting strake ... right where the transom strap falls when trailering ... which is how we do things :facepalm:

I can go further outboard with the transducer, but that will bring it out of the water at plane, I believe. I could re-situate the transom strap, but that would bring it in to attach to the bunk (as opposed to the frame) which I'm leery of doing.

Any other thoughts?

 

[Scott Danforth]

Relocate the trailer tie points

 

[dingbat]

With a conventional transducer you want to be at least 3” off the tip of the prop.

Side scan teansducer go out a bit further to get past the lower unit.

Find it hard to believe that any part of the transom is out of the water on plane. Transducer only needs to be 1/2” or so below the water to work.

 

[Alumarine]

I'm 13" with my transducer and it works fine.

 

[southkogs]

You can see the waterline where the boat sits at rest, or just puttin' along. I agree dingbat, I don't think the outside strakes out out at plane (never hung my head over the end at speed to check ), but I didn't know if I was far enough below the boat. I might be over thinking it. moving the unit out another few inches probably helps with my cable to the head unit anyway.

I may not get to this today, so any other thoughts are welcome.

 

[southkogs]

Relocate the trailer tie points

Thought about that too. But, I really creep out at the thought of punching holes in my hull. The Transducer cable hold is already making me nervous and it's going to be well above the water line.

 

[Scott Danforth]

the points on the trailer..... not the hull.

 

[MTboatguy]

My last boat, I had my transducer was about 9" from the engine and it worked fine. The current boat I just purchased had one on it and it was only about 6" from the engine and the guy told me it worked fine, but I am going to mount a little farther away from the engine than he did. One thing nice about it, this is a Starcraft and I can run the wire up and through the splashwell drain hole so I will only have to drill the small holes for the transducer bracket.

 

[roscoe]

My Helix transducer is 13" from centerline.
The transducer for the bow sonar is 9" from center.

Both work fine and at speeds up to 25 mph.

These are DI and conventional units, not side imaging.

I would mount just inside the strake.

 

[southkogs]

the points on the trailer..... not the hull.

Thought about that too ... but the cross member on the frame is back another 6" or so. Makes attaching the strap a real pistol. There's a metal structure under the bunk that you see in the image, and I don't think that's a good point for attachment, agreed?

If I come in from the strake about 3" or so, that might do it. I'm not getting to this today anyway, so I'll mock something up tomorrow and see what the consensus is. We're going out after church so, I won't be glueing the transom saver on until Monday or Tuesday. Gotta' get some mounting hardware too. Didn't realize I was short on some bolts for the dash mount.

 

[dingbat]

I might be over thinking it. moving the unit out another few inches probably helps with my cable to the head unit anyway.

let me throw a wrench in your thinking.....my thru-hull transducer is on center of the prop.

What is the setback and elevation difference between transducer and prop?

 

[89retta]

I have my Helix transducer mounted about 6" from the center. Works perfect and always an accurate reading . From 0-45mph

 

[82rude]

Not sure about glass but I have my transducer shooting though the bottom of my ss160 starcraft..I simply epoxied the thing to the inside and it works just fine .

 

[Scott Danforth]

Aluminum hulls work better for shooting thru the hull. Can be done with fiberglass, however any voids in the glass and it reads wonky

 

[southkogs]

Not sure about glass but I have my transducer shooting though the bottom of my ss160 starcraft..I simply epoxied the thing to the inside and it works just fine .

The only places I can think of where I'd have glass that goes directly to the water (not having to pass through the sole and the hull) are the ski locker and the bilge. Can you try it by simply bracing the transducer down? That would be pretty easy.

 

[southkogs]

Okay - so, this might work:


That puts the center of the stern saver 12" from the edge of the transom plate. The strap is clearing it pretty well. I'll just have to fiddle with the cable. I'll also mess with placing the transducer inside before I mount it. Will head out on the water later today for a while, so nothing gets hard mounted today.

Dingbat: The way my trailer sits here at the house, I can't get the drive down far enough to give you good measurements. I'll take some a little later. Maybe this photo helps:

 

[southkogs]

In the spot I show with the blue tape, the transducer would mount about 26" behind the prop hub and about 16.5" above the center of the prop hub.

While we were out on the lake I tried fixing the transducer to the center of the bilge as far forward as I had a flat spot. I taped it down pretty tight with gorilla tape figuring if I could get a sensible reading an inboard mount might be possible. LOL ... the readings were pretty schizophrenic. Otherwise, the the plot part of the head unit was pretty fun to monkey with.

 

[ab59]

Stupid question I know but if you are worried about the tie down straps being in the way , why don't you just run them up to the ski rope tie and leave the ties at the trailer where they are ?

 

[southkogs]

Stupid question I know but if you are worried about the tie down straps being in the way , why don't you just run them up to the ski rope tie and leave the ties at the trailer where they are ?

Tension forces are different. Ski eye isn't really designed for that, and (unless I'm way off my rocker) actually a weaker point than the transom eyes.

It's cool. I mounted the stern saver last night roughly where it is in the photo above. I can route the cable to it no problem. Head end has been installed up front at the first place I'm going to try it. I'm a little worried about needing to reinforce the mounting point, but I'll try it on the lake first and see how it goes.

If I can get to it before the weekend, I'll get the transducer mounted. If not, that may wait a week or so. Work has been BUSY.

 

[MTboatguy]

Actually those ski eyes are pretty darn tough, I have broke things in the past, but never have I broke or pulled a ski eye out.