Best transducer location?

[PyrateJim]

I have a 1983 Sea Ray, 360 express cruiser (40' LOA w/14' beam) with twin tunnel drive inboards. I am mounting the transducer for my Hummingbird 797c2 si, in the next couple of weeks. My question is, where on the transome is the best place to mount the transducer to avoid any interference from the prop wash. I am thinking above the drain plug and below the large anode, but want to make sure there is no place better suited.

Although I dont have access to a picture of MY boat, from under the swim platform and below the waterline, this one is pretty close to what I am looking at.

I am also considering going with a mount that is portable, so I can go from the main boat, to the dinghy if need be.

 

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[FISHEYE]

I would put the transducer as far forward near the bow if possible.Thats where mine is on my boat.Mine is mounted inside the hull and epoxied to the hull.I get just as good reception as if it was mounted on the outside.Also being further forward you have no bubble interference and have time to react to shallow water obstructions.Like stopping the boat or turning to port or starboard.Plus if the transducer is mounted inside the hull theres no cleaning the barneys off it or ripping it off the hull if you happen to hit something like those manatees(speed bumps).

 

[PyrateJim]

I would put the transducer as far forward near the bow if possible.Thats where mine is on my boat.Mine is mounted inside the hull and epoxied to the hull.I get just as good reception as if it was mounted on the outside.Also being further forward you have no bubble interference and have time to react to shallow water obstructions.Like stopping the boat or turning to port or starboard.Plus if the transducer is mounted inside the hull theres no cleaning the barneys off it or ripping it off the hull if you happen to hit something like those manatees(speed bumps).

Can I use the same transducer as a "through hull" that I would otherwise mount on the outside, just mounted on its end?
I have to remove the sub-floor in my salon and the sound-proofing under that. It would be about mid-ship and would be the perfect place to mount. Does it have to be "in water" or can it be dry and epoxed as you mentioned?

 

[FISHEYE]

You should check with the manufacturers recommended install for your transducer.I know most airmar tranducers can be epoxied to the hull,dry.And airmar makes transducers for just about every fishfinder on the market.Check with humminbird to see if its a airmar tranducer.Or check this link once you find out what model it is.

http://www.airmartechnology.com/2009/products/installation-owners-guide.php

http://www.flickr.com/photos/45667123@N06/4500884066/in/set-72157623063888483/


http://www.flickr.com/photos/45667123@N06/sets/72157624259072397/

 

[stevemc]

I used to be a marine electronics rigger, and I have put some transducers in the hull, not drilling a hole, just epoxied inside. What you need to do is, have the boat in the water, and near the center, hopefully pointing fairly straight down, put water in the area that you want to use. Then with the transducer hooked up to the fish finder, lay the transducer in the water, in the area that you have chose. If it is good, pump out the water, dry it, clean it good with acetone, and make sure you have no bubbles, and with the fish finder on, lay the transducer in place. Use epoxy thickened with cabosil to a mayo like consistancy. If the boat has any coremat or foam in the hull, this wont work. That is not usually done below the waterline, but many sailboats, especially fast ones, like catamerans have foam cores even below waterline. BUT, I am not so sure the side scan transducer will work so good like this. I feel it has to be fully in the water. You could have 1 trancducer and move it from boat to boat, but it would be better to have a dedicated perfect working transducer, and another portable one mounted on a sturdy board that can be clamped on the dingy. You could have a composite board-fiberglass, or some other sturdy board, and slide it up between the swim platform and the transom, and mark where it is perfect. Unless your swim platform is a solid fiberglass with no opening there. And then somehow hold it in place, maybe with a wedge between the transom and the board. As for a good spot on that boat for a transom mounted transducer, call the Sea Ray dealer. But I would say on the center pod part between the prop tunnels. You need the lower face to be at a very slight angle to get hit with clean water. If it is up above the plane of the bottom, it wont work. Same with the board thing, get the transducer down in the water flow. Just the face of the transducer. But as Fisheye said, for a thru hull mounting, forward of the running gear is good. On bigger boats, it is usually near the deepest point, but just uphill of that on the hull, not the keel. Some high speed boats, such as certain Donzis, Jupiters, and a few others, have a flat area in the center of the boat, on the keel. Donzis sometimes have hydroplane hull ventilating things, that raise hell with transducers. Like Fisheye said, Airmar makes thru hull trandsucers that are at the angle of the hull, no drag. But for your boat, you would need a right and left Humminbird side scan through hull on each side. Transom mount should work ok.

 

[rgecy]

PyrateJim,

You are going to have issues with a trasom mounted transdcuer on that boat. If you mount it near the drain plug you will probably get good 2d readings, but the prop wash will cause major issues with the side imaging. You will need to purchase a thru hull SI transdcuer from Humminbird.

This will need to be mounted forward of the props and depending on your keel, you may need to go with a dual transducer setup with Y cable.

I have had some guys get creative and make extensions, etc. to get below the prop wash or keel. Check out the installation pictures on my forum for some more ideas. http://forums.sideimagingsoft.com

Feel free to contact me directly if you have any questions.

Good Luck,

Robert

 

[SimonLakeSub]

I have a 25 foot steel boat, and am planning on buying the 1198 side scan. I would go with the thru hull transducer. The gentleman in the store said one transducer would be okay. Some one else thought 2 transducers would be better.

My question is, would one transducer give me excellent results.

Thanks, Simon....

 

[ScrugneysGunDogs]

I have a 1983 Sea Ray, 360 express cruiser (40' LOA w/14' beam) with twin tunnel drive inboards. I am mounting the transducer for my Hummingbird 797c2 si, in the next couple of weeks.
I am also considering going with a mount that is portable, so I can go from the main boat, to the dinghy if need be.

A 40 footer with a portable transducer I've never seen that one before. The key to any transducer is to mount it in the correct place. It needs an unobstructed view and a clean, bubble free flow of water over it. It will only be as good as the mounting job. I suggest you hire somebody to do the installation - it matters that much.