?'s for mounting transducer on boat

[racohoon]

I just bought a Pirahna 4 fish/depth finder. I have a 18 ft Stuery modified?/tri-hull fiberglass. I beleive it is what is reffered to as a "stepped hull" towards the rear of boat @ the bottom of transom. The instructions say "stepped hulls require the transducer be mounted on the step if possible.Never mount the transducer on the transom behind the step". <br /> Every boat I have ever seen has it's transducer mounted at the bottom edge of the transom (facing rear of boat)just off to one side of the motor. Is this making reference to mount it on the transom to the side of the step (for turbulance reasoning?) or to actually mount it under the boat to the bottom of the hull(facing the ground?)? My common sense tells me to run the boat @ higher speed and check for turbulent areas and choose a non-turbulent area on the bottom of the transom and mount transducer (facing the rear of boat) not mounted on the bottom of hull (facing the ground? This should not require this much thought, should it??

 

[blifsey]

Re: ?'s for mounting transducer on boat

It mounts on transom not on bottom of hull. Directions are telling you NOT to mount on transom directly in line with the step transition but somewhere between keel at step transition. You need to look at underside of hull and ID best location where there will be no turbulance. Also, keep in mind you want to mount where trand. will be barely in water on plane so you get a reading while running also.<br /><br />BL...

 

[oldboat1]

Re: ?'s for mounting transducer on boat

Try simply placing the transducer in the bottom of the boat, inside the hull (face of the transducer has to set on the bottom of the hull). It may work just fine without any additional drilling or mounting (may need to find a way to keep in stable -- perhaps just placing a small bag of sand or something similar over it to keep it in place.)

 

[Franki]

Re: ?'s for mounting transducer on boat

Its simple really.. <br /><br />Take the boat out.. go as close to WOT as you can, and take a look over the back of your boat.<br /><br />You need to find the area at the back of the boat,, where there is the least amount of turbulance.. and if at that speed the water is still directly under the trasom with no gap.. I'd consider putting it on the transom. (in the area with the least turbulance.)<br /><br />If that doesn't work, find a place on the inside of the hull, at the lowest point you can preferably, and again somewhere that you don't think there will be alot of turbulance..<br /><br />you can use an epoxy resin to stick the transducer to the inside of the hull... I have seen it done like that with success on fiberglass hulls. (make sure there are no air bubbles trapped between the transducer and the hull.)<br /><br />but your best bet, is to actually try mounting it in dummy possitions, (use a weak glue or something and try it in various places till you find a good compromise..)<br />Its nearly all "trial and error" you just have to give it a shoot.<br /><br />rgds<br /><br />Frank

 

[oldboat1]

Re: ?'s for mounting transducer on boat

See Frank's instructions on finding the location for transom mounting. If you go that route, use the instructions with the unit to do the actual mounting. It's not rocket science -- BUT try just putting it down inside the hull first, if you have access. That worked just fine with my 17' runabout, and it is obviously an easy way to go (and still leaves all mounting options open, of course). I strongly recommend against putting any kind of adhesive (or anything else, for that matter) on the face of the transducer. If you want to get fancy after deciding where to put the transducer, put a large blob of 3M 5200 on the dry boat bottom (again, mounting inside). Wrap the transducer in plastic wrap, and push it face down into the adhesive. Mold the stuff around the transducer to keep it in place. When you remove the unit, the plastic wrap will have kept the face of the transducer clear.

 

[DJ]

Re: ?'s for mounting transducer on boat

racohoon,<br /><br />When I mount transducers to the transom I generally mount a nice looking board, or better yet use "Starboard". That way, you can move the transducer around, for best performance, on the transom without turning the transom into swiss cheese.

 

[Boatist]

Re: ?'s for mounting transducer on boat

I found the best place is usually right next to speedo pickup tube or on in same location on other side. Shooting thru the hull works well on straight fiberglass but has about a 10 percent or more loss on most boats today where hand layup method is used. To find a good location can build some dams with clay around transducer fill with water so no air is between the transducer and hull try several spots.

 

[racohoon]

Re: ?'s for mounting transducer on boat

Thank you for all the info guys. I took her out and let the wife pilot (first time behind the wheel!) while I looked over the transom. WOW!! never realized how far out of the water my boat and motor actually were @ wot! <br /> It looks like the best place is next to speedo pick-up. My personal preference leads me away from mounting in the hull, sorry guys. I want to be able to remove this if I sell/trade boat. So I am not going to be drilling holes in the transom for cable,just the mounting bracket screws.(Cable w/ be routed thru the opening for steering cable to motor.) Thanks again for the great help you have been, seems folks here are never disappointing

 

[blifsey]

Re: ?'s for mounting transducer on boat

Most I've seen do as you describe with the cable. Still be sure to put some sealant on the screws for the mounting bracket. I used 3M 4200 when I did mine. They say 5200 is "permanent" and can't be removed. Don't use silicone for this since its below water level. Another option, search some older posts that describe mounting a small piece of starboard with adhesive and drilling screw holes in it. I would still feel more comfortable screwing the starboard in at least above waterline.<br /><br />BL...

 

[oldboat1]

Re: ?'s for mounting transducer on boat

Well, I still recommend trying to shoot through the hull -- simplest set up, if doing a temporary mount, and the best if you are concerned about removing the unit when you sell your boat.<br /><br />If screwing to hull, however, I would recommend the 3M 5200 for mounting. It's a good adhesive above or below the waterline, and stays flexible. You can easily remove it from the flat surface of the transom with a razor blade or something similar. Predrill the gelcoat in the right diameter for the screws (not too small) or you will end up with cracking and chipping.