Afraid to install transducer on aluminum boat.

[bcassedy]

The previous posts work well (thru hull / transom mount). One other consideration beyond the fish finder part of this thread is the depth finder section.
Our boats, being longer than, and with more draft than smaller, lighter boats, benefit from having the transducer mounted as a thru hull somewhere amidships. Approaching a shoreline where the bottom creeps up gradually (think river banks / mucky bottom) is a perfect instance where it's good to know how much water is under the bottom amidships. This gives you the chance of possibly rethinking beaching in one area where the props could chew up a lot of ooze that would be pulled into the engine thru hulls when backing out.

This also affords the use of the supplied cable without the need of an extension.

Sunset Seeker only had the 1 upper station depth gauge when we bought her. I always wanted another unit at the lower station for peace of mind (and being an IT guy "knowing anything, using somethings" is second nature. ) so I installed another unit with a thru hull. As the advice given notes, measure, measure, measure and then cut/saw. I installed the thruhull on our 32' just aft of the access panel in the galley area. The thru hull's plastic so I didn't have to worry about dissimilar metal contact (brass to aluminum). I bedded the transducer's flange with 5200 sealant, as well as around the threads AND the rubber backing gasket. When the backing nut was tightened down, there was a minor amount of sealant that oozed out. This is good, guaranteed that all areas were coated (not leaks, no sink! ). I check periodically just to make sure it stays leak free.

Bill

[barkleydave]

Nice to see an active discussion! As you can tell there a variety of ways to mount transducers. Probably the most common is the transom mount transducers. On my 87 there are two. They have been on the boat since 87 with NO issues regarding the mounting. No fairing block is required since our transoms have little dead rise and the mounts provide for plenty of angle adjustment. They are mounted directly to the transom with SS bolts and 3M 5200 sealant. Use lots of sealant inside and out. Do not tighten the bolts all the way down. Let the sealant cure for a few ours then snug them up. Since there will be no water intrusion there will be no corrosion.

I really like midship mounted thru hull transducers. I have installed a few on aluminum hulls. Currently there is only one company I know of that sells a puck which will work on our hulls. The company is called Alumiducer. I contacted them a few years ago and they were confident that their unit would shoot through our hulls. They are tricky to install. You actually are creating a "wet box" of pure silicone sealant for the transducer. Any air voids and it will not work properly. The few I have installed were not as sensitive as a direct water transducer. I just noticed they have a new unit that they claim has zero loss.

Here is their site for more information.

http://www.radarsonics.com/AlumaDucer.htm

http://www.radarsonics.com/Spec%20Data% ... aDucer.pdf

Safe Harbors,
dave

[Busia]

I would prefer a thru hull transducer, tried one that did not work, so mounted mine off the transom. The Alumiducer may or may not work. I see they rate it for a skin thickness up to 0.12 inch. My 32' hull had 5/32 skin which is slightly more. Even a vessel with 1/8 inch plating will be 0.125 inch. The 0.005 is just a hair (your choice ) over the specs, so will it work? Bunch of coats of bottom paint will be a lot thicker, but I would consider trying it as I don't like to put holes in the bottom of my boat.---Ed

[Aquaholic]

Thanks Jeff!

[Boatin2]

I'm glad I checked this thread. I was about to post one about this very thing. The P.O. had a brand new airmar thru hull and cut the cable I am assuming so no one else could benefit from it . We floated without one last year but bought the Lowrance Elite 5 over the winter and it came with a nice transom mount transducer. I had the exact same questions because I too am not crazy about putting more holes in my boat. I did find a plastic thru hull transducer Airmar P319-Dt-BL 600W through Imarineusa. But because of everything I've seen on here and the cost I think I am going with the transom mount that came with the unit. We have much to get done on her before we splash this year as last year was year 1. Bottom paint, depth finder, impeller, carpet..... The list grows every time I look at it

[Busia]

I have a separate depth finder, but I put in a Lowrance GPS last year. Good equipment but terrible instructions. Factory sent instructions for the wrong unit. Many calls to tech support finally figured it out. (in the USA ) So if you have any questions call them up. I would buy their stuff just because the tech support is so good. People that speak English and know what they are talking about.