Keel Mount Transducer

[daaaddy27]

I'm doing it!! I'm mounting my transducer on the keel!

I've always felt like this is the optimal place for a transducer for sidescan and I was trying to think of how I can pull it off. I decided to melt a small cutting board (HDPE which I believe is the same as starboard???) at 400 deg F for a little over an hour and then molded it to the keel. To keep it from sticking I sprayed cooking oil on keel. At the base I used a trowel, which helped create a flat surface that I will attach my transducer to. After a couple minutes the plastic was cooling, and wasn't moving as much, so I threw it in some cold water to cool it down and solidify the mold. Here's where I'm at in the process. It looks like crap but I'm like, whatever because it will be in the water.


Next step is to trim some of the excess plastic, fill in the gaps with JB weld epoxy, then sand everything down to make it look halfway decent.

 

[Dixemon]

Interesting concept. I wouldnt think anything would adhere very well to the hdpe, such as jb weld. I would be curious if it would. Also, how do you plan on attaching it to the keel? Screws, bolts?

 

[daaaddy27]

Interesting concept. I wouldnt think anything would adhere very well to the hdpe, such as jb weld. I would be curious if it would. Also, how do you plan on attaching it to the keel? Screws, bolts?

Hmm, guess I'll find out with the adhesion, lol.

Plan is to countersink 2 bolts on each side + 4200

 

[Dixemon]

If that doesnt work out, you could also look into a small sheet of 1/4" kydex. It will mold to that shape pretty well, you could also pre mold it around something flat to mount transducer to then finish molding around keel. Although that area is going to take a lot of punishment above planing speed, so theres that. I think thats why its such an eyebrow rasing location.
Are you not worried about ripping it off in that location? None of us plan on hitting bottom or logs in the water but......

 

[daaaddy27]

If that doesnt work out, you could also look into a small sheet of 1/4" kydex. It will mold to that shape pretty well, you could also pre mold it around something flat to mount transducer to then finish molding around keel. Although that area is going to take a lot of punishment above planing speed, so theres that. I think thats why its such an eyebrow rasing location.
Are you not worried about ripping it off in that location? None of us plan on hitting bottom or logs in the water but......

well the 5-min JB weld didn't hold, peeled right off. I think before the kydex I may just hit it with my orbital sander to flatten it out. And then use my multitool to trim it a bit.

At planing speed do you figure that area will take more of a beating than if I were to mount it on the ride plate?

I mean, I don't plan to hit bottom or logs, but I guess I never thought about that possibility. I primarily boat in Lake Huron so it's all fairly deep. And that is lowest part of the boat.

 

[Dixemon]

I would say the mounting bracket would take alot of heat there unless it was seamlessly installed to the hull. Mounting to the ride plat wouldn't be as bad imho.

 

[HangOutdoors]

FWIW, I guess I am unclear why you would mount in there and screw with your keel? The ride plate works fine, and as long as you have a max of 5 degrees off the keel you will get 100% side scan. I would also think it will cause some weird drag issues and potential speed loss and another possible leak area if you drill it there. Myself as well as many other members here have ours mounted to the ride plate and it works fantastic with no side scan loss.

You hit something good, like a floating log and it could tear your keel off or at least bust it up quite good. Bad place to have water pumping in, in Lake Huron. Major repair and boat out of commission.

FYI, cutting boards are not the same as Starboard. Most cutting boards have issues with UV and will deteriorate.

An aluminum mount on the ride plate is very secure and if something does hit there, which is much less likely, the aluminum will sheer off and most likely the transducer, but it should not cause any damage to the boat. Just need to craft a new mounting plate and install a new transducer.

 

[daaaddy27]

So when you mounted to your ride plate, did you use the two bolts that attach the ride plate to the boat or did you drill new holes?

 

[Dixemon]

I used existing holes in the ride plate.

 

[daaaddy27]

Thx. What did you use to reseal?

 

[HangOutdoors]

@daaaddy27
No I did not use existing bolts. Personally would recommend against. But up to you of course. I decided I didn't want to mess with those and I wanted the mount out a bit further to the side. Just drill the holes, it drills easily. I also didn't want to use the existing holes and break the seals and in case I hit something and it causes an issue with the existing ride plate mounts.

Aluminum bracket so it will sheer off and Stainless Steel bolts, washers and nylon insert lock nuts.

Finally give yourself a bit extra on the cable that way if you decide to move it later or change it you can. I have about 4 inches of play but it is secured above the jet.

 

[daaaddy27]

@daaaddy27
No I did not use existing bolts. Personally would recommend against. But up to you of course. I decided I didn't want to mess with those and I wanted the mount out a bit further to the side. Just drill the holes, it drills easily. I also didn't want to use the existing holes in case I hit something and it causes an issue with the existing ride plate mounts.

Aluminum bracket so it will sheer off and Stainless Steel bolts, washers and nylon insert lock nuts

Ok so you went all the way through the ride plate and hull then? It wasn't clear if you pre-drilled holes to not go through the ride plate, and then used short screws + an adhesive sealant to secure them.

 

[HangOutdoors]

You see I mounted it to the left of the ride plate holes. Didn't have to go through the hull at all. Also I am still on the flat of the ride plate. I wanted the mount further away from the keel so it doesn't create a catch where things could get stuck.

Also in the pic I no longer use the splash shield and the arms are shorter. I move it up a bit. Nice thing is you can just change arms to your desired height.

In the pic below you can see where if I do hit it, it will only rip off the transducer and part of the mount.

 

[HangOutdoors]

One nice think about mounting it like this and not fixed is I did roll over something in some shallow water and the transducer kickup up. I keep it fairly snug but use star washers on the inside where it mounts to the transducer so that it can kick up.

Not the prettiest mount, but works great. Figured I could have a shop fabricate a welded one out of aluminum if I ever get around to it. Wanted to mess around with height and such before I took it that far.

 

[daaaddy27]

I see. I like it.

Question: do you notice any drag on the port side? If so would modifying your setup to position the transducer under the keel and utilize the port and starboard ride plate? That way you have symmetry? Like this


Rubber brass well nut for vibration and keeping the aluminum center.

Or do you not notice any drag?

 

[daaaddy27]

Please excuse my obsession with having the transducer centered on the boat

 

[HangOutdoors]

No Drag, no issues, no speed loss, no spray. I also have Trim Tabs, which if you boat in Lake Huron, I would guess you would get sooner or later, and they don't interfere. Again many, many members here use this setup with out issue so it has been battle tested fairly well.

I boat in Lk. St. Clair, Lake Erie, Lake Michigan and Inland lakes here. No issues.

TBH, fully below the stern keel is just to low in my opinion. Your last pic I would think that it would cause you some performance issues.

Finally if you set it up like I am showing and you decide you want to change it or move if that is your desire, just unbolt it and move on.

 

[daaaddy27]

No Drag, no issues, no speed loss, no spray. I also have Trim Tabs, which if you boat in Lake Huron, I would guess you would get sooner or later, and they don't interfere. Again many, many members here use this setup with out issue so it has been battle tested fairly well.

I boat in Lk. St. Clair, Lake Erie, Lake Michigan and Inland lakes here. No issues.

TBH, fully below the stern keel is just to low in my opinion. Your last pic I would think that it would cause you some performance issues.

Finally if you set it up like I am showing and you decide you want to change it or move if that is your desire, just unbolt it and move on.

Gotcha. I appreciate all the insight.

Yeah I just installed trim tabs and that’s why I’m trying to find a new place for my transducer.

 

[HawaiiBreeze]

I'm on board with NO HOLES in the boat below the water line. I mounted mine on the Ride Plate too. I'm single engine and the mounting was on the port side. I feel no pull or drag to port at all.

 

[daaaddy27]

Did my best to replicate your setup. I’m mostly happy with it. Think I should move it up a cm or two.

A screw didn’t fit in the transducer and I plan on removing it. And then one of the mounting bolts to the ride plate didn’t fit the pre drilled hole. Gotta fix that also.