Jon Boat Transducer Transom Mounting Location

I have a relatively new Alumacraft 1648 flat bottom jon boat I am slowly modding. My next project for it is mounting my transducer and RAM mount for my Helix 5 SI/GPS. I just bought a Bert's Custom Tackle mounting board and tube of 3M 5200 so I have everything I need.

The boat has 5 total strakes on the bottom, 1 down the center and 2 on each side. I didn't measure the spacing but they look even so that would be approximately 8" between them. Two of the 8" gaps have rivets in it but each appear to have a few inches in the center that are rivet free. This is the innermost and outermost gaps. The center gap has a few extra rivets in just the stern due to the transom bracing. Any advice on which is the best location to mount the transducer? Would those rivets that are only present in the last foot or so of the stern cause air bubbles like a row spanning the entire hull would?

Here are some pictures for reference.

http://i1175.photobucket.com/albums/...psvbayfbxa.jpg

http://i1175.photobucket.com/albums/...pspxeg5kfr.jpg

http://i1175.photobucket.com/albums/...psoh3kbcrx.jpg

http://i1175.photobucket.com/albums/...pslcgeca0n.jpg

http://i1175.photobucket.com/albums/...pswpqehqu4.jpg

Slower speed scanning is usually not an issue because the boat sits in the water lower and not as likely to create aerated water at the slower speed ...

As the boat speed increases, rivets can be challenging sometimes when trying to find a suitable mounting location ...

Some have fabricated a temporary mounting board that can be securely C-clamped to the transom for testing for placement options ...

My guess would be exact center between 2 strakes in your case ...

Rickie

Quote:

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Originally Posted by rnvinc

Slower speed scanning is usually not an issue because the boat sits in the water lower and not as likely to create aerated water at the slower speed ...

As the boat speed increases, rivets can be challenging sometimes when trying to find a suitable mounting location ...

Some have fabricated a temporary mounting board that can be securely C-clamped to the transom for testing for placement options ...

My guess would be exact center between 2 strakes in your case ...

Rickie

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That is some good info. The plastic mounting board I purchased is 12" wide so I may be able to place it on my transom so it captures the middle of the center "gap" and the outermost "gap". I could then try both locations.

And as you mentioned the SI and DI functions would be used off of plane so I would agree, turbulence would be less and hopefully negligible for accurate readings. I guess ideally I could put the SI transducer in the center gap and get a regular sonar transducer to put on the outermost gap to get high speed depth readings.

But that aside, is there any reason to not place the transducer in the outermost strake gap (see my 4th picture)? That location is far away from the prop and has a strip clear of rivets...but would also only be 3-4 inches from the side. I'm not sure if being mounted that close to the edge is a potential issue or not. But that location seems like it would the best location given the hull design assuming that close to the edge is ok.

I like the idea of a testing board to mount to the transom though. I will give that a shot before I do anything I think. I guess it's just as simple as using a really rigid board and clamping it on?

Quote:

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Originally Posted by scout-j-m

I like the idea of a testing board to mount to the transom though. I will give that a shot before I do anything I think. I guess it's just as simple as using a really rigid board and clamping it on?

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Correct ... Just use a board stiff enough ...and C-clamp it well ...

You wouldn't want it to come loose and get into the prop ...

Rickie

Good luck is a requirement.

Quote:

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Originally Posted by Cane Pole

Good luck is a requirement.

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Definitely not something I have! LOL

Scout I did the same thing you've doing on the about same size boat. It will work. But instead of screwing the board in, I riveted it with 1/4 buck head rivets likes in the boat already. Water tight, no leaks. Got them at fastenal in CULLMAN near you. Same rivets they use in 52 " trailers ( semi truck). Or you can get them at Fleetpride.

Quote:

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Originally Posted by EarlWaynetom

Scout I did the same thing you've doing on the about same size boat. It will work. But instead of screwing the board in, I riveted it with 1/4 buck head rivets likes in the boat already. Water tight, no leaks. Got them at fastenal in CULLMAN near you. Same rivets they use in 52 " trailers ( semi truck). Or you can get them at Fleetpride.

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Earl ... Could you post some pix of your mounting board/xducer installation ...??

It may help some following this thread ...

Rickie

Will do Rickie. I take a pic tomorrow.

Quote:

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Originally Posted by EarlWaynetom

Scout I did the same thing you've doing on the about same size boat. It will work. But instead of screwing the board in, I riveted it with 1/4 buck head rivets likes in the boat already. Water tight, no leaks. Got them at fastenal in CULLMAN near you. Same rivets they use in 52 " trailers ( semi truck). Or you can get them at Fleetpride.

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Thanks! That's a good point and one I didn't really consider regarding the fasteners. I may use rivets since I have some on hand. I may also just use SS machine screws/washers/nuts.

Ok Rickie and Scout, here are the picks and buck rivet I used. On a side note the absidy cable is defective from Hummingbird. They have had a bad batch here lately. They are sending one by mail that's been tested.
Attachment 247715

Ok.
Attachment 247717

Where did you get the mounting board Earl ... ??

Some may find that info helpful also ...

Rickie

I finally got mine on last week.

These newer Alumacraft jon boats have the rear bench extended to the transom on the sides so there is not access to the inner/sideportion of the transom for using nuts/bolts or rivets. So I decided to just attach it solely with 3M 5200. That stuff is messy but it is solidly on there.

To prep the boat, I just lined the board up where I wanted it and put masking tape around it. I Cleaned the area with a damp cloth and then followed it by wiping with acetone. I then lightly sanded the area and re-wiped with acetone. To prep the board, I used a small router to cut some 3/16" groves in the backside, then roughed it up some with bi-metal jigsaw blade by holding the blade in my hand, then finished it off with some coarse sandpaper and acetone wipe down. I would have used a dovetail router bit but apparently didn't have one.

I applied a liberal amount of the 5200 to the board and put it in place and clamped a 2x6 to the top of the transom and to the rear trailer cross member to hold it in place. I tapped the board into the exact location and leveled it and then removed the tape. This was fast cure 5200 so it only took a day to cure.

http://i1175.photobucket.com/albums/...psvjlmqaw5.jpg

http://i1175.photobucket.com/albums/...ps5x89dpwv.jpg

http://i1175.photobucket.com/albums/...psnw7xymry.jpg

It doesn't look perfect and I got a little 5200 on the outside of the board and on the transom but that's the price you pay when you tackle a project on a weeknight when the days are shorter. Even with lights its hard to beat regular sunlight. I have the transducer mounted as well but don't have a pic yet. I'll add one of the final product soon.

Looks fine to me.

I use an adjustable mount from Cabela's. Allowed me to move it around to find the optimal location for performance without drilling holes.Attachment 250696Disregard pic #2 of the air handler. It won't help you:yikes