Transducer Install

'84_241_Offshore

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Need to replace a transducer on my '95 268 Islander which has the stepped hull.
Currently the transducer is mounted on the "vertical" surface which is approximately 24" fwd of the transom.
In this configuration the cable for the transducer goes through the hull below the water line.
Whoever installed it originally sealed the opening with what I believe is some type caulk.

Just checking if this is how transducers are installed on hulls like this.

Any feedback is welcome.
 

DennisG01

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In and ideal world, you'd drill a hole above the waterline. But if you can't do it, you can't do it. The only option is to bring the cable around the back end and up to another spot which is above the waterline. Would look pretty shoddy, though. But that's your call. That's about it for options, right?

If they did the hole the "best practice" way, they completely saturated the core (assuming - not sure exactly where you are saying it's going through) with epoxy, first. Check for that.
 

'84_241_Offshore

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Thanks for the response Dennis.
Found this on the WWW this morning..........doesn't seem like its made for transducer sized cables........
 

deepdesire

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84 241 Offshore I have a 96 Islander with the same hull. There are two flats for transducers on that hull. I was thinking about mounting a totalscan transom mount but could not bring myself to do it due to cable routing. One possibility I considered was bringing the cable though the top of the trim tab pocket. I decided to mount a single totalscan thru hull on the keel. Have yet to drill the holes but that's the plan. I have a B744 with a hi speed fairing on the starboard side. That transducer reads great even at high speed.
 

'84_241_Offshore

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Thanks deep.....I am actually replacing a transducer that was already installed, not looking into drilling another hole(s).
There are actually 2 transducers in this location w/ both the cables going through the same hole.
Guess I'll clean-out the existing hole as best as possible, coat w/ epoxy and caulk the sh!t out of it!
 

DennisG01

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Thanks for the response Dennis.
Found thison the WWW this morning..........doesn't seem like its made for transducer sized cables........
So... you found "nothing"? :)

All you need is a simple clamshell. The clamshell captures the cable to keep it somewhat stationary and also gives a much larger area for more sealant. Don't forget to epoxy the clamshell screw holes. Ideally, oversize drill the hole, fill completely with epoxy, then come back and drill your pilot hole. This way, if any water would intrude, it's only touching plastic.

Use a GOOD sealant. BoatLife LifeCaulk would be my choice.
 

DennisG01

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The word "this" contains a link...........
Ah. I see it, now. Was it colored blue before? I missed it. All I saw was a bunch of white space where I thought a picture should be.

I don't know that I'd trust that for below the waterline. "Waterproof" above the waterline is different than below the waterline. That said, I've never had one of those in my hand to say for sure.

But if you do the oversize drill/fill with epoxy/redrill the size hole you need... nothing beats that. You will have completely protected the core. Worst case scenario is that the sealant breaks down after a couple decades and water starts leaking into the bilge - but it won't get into the core so it's really not a big deal since it would only "drip" in.
 

GradyZ

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Hi Guys, I purchased a 95 Islander this past November and was thinking of upgrading the Lowrance Ti9 Elite on it with a Raymarine Axiom 9. All this to say I was hoping I could possibly repurpose the existing thru hull on it but, the chances of it being compatible with the Raymarine are slim Im thinking even if I got a cable to convert the pin config.
Boat Transducer and Zinc.jpg

84 241 Offshore - have you finished your project? Any advice on what you encountered?

I may just save myself the hassle of trying to reuse the existing in the event I refit it to the new Raymarine then find out the thing is fried and useless.

Other option is to install the new one over on the other side of the hull to have a direct spec hole for the new transducer to make it as tight as possible...

Is that the zinc in the blue box btw?

Thanks!
 

freddy063

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I just picked up a in hull transducer , have you looked at them. Mounts inside the boat. Many advantages , nothing to hook lines and stuff on. No holes. Mounts from the inside. Just an thought .
 
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ScottyCee

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I really don’t know anything about the through hulls. Are there some high end ones these days? I have the same abandoned old green paddle wheel fitting on mine, but if there’s a good option to replace it and use that spot maybe that’s a good idea. I’ve been fretting over the old one, but maybe I should consider using a new one of that style. I am running an HDS 10 GEN two non-touch.

how about this one:

or this one has the same connector that my unit has:

 
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Holokai

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I just picked up a in hull transducer , have you looked at them. Mounts inside the boat. Many advantages , nothing to hook lines and stuff on. No holes. Mounts from the inside. Just an thought .

You will get some signal/resolution loss due to the transducer having to shoot through the fiberglass but it’s not too bad unless you’re deep dropping for snapper (over here that can mean 1000’+). I had a cheap 500W Garmin in-hull in my last boat and it worked fine for up to 300’ in saltwater. If I end up installing one on this boat it will be 1kW Airmar as you can get the same model transducer with manufacturer-specific input plugs. The higher end Airmar unit have more elements and perform multitudes better than most fishfinder OEM transducers.
 

freddy063

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You will get some signal/resolution loss due to the transducer having to shoot through the fiberglass but it’s not too bad unless you’re deep dropping for snapper (over here that can mean 1000’+). I had a cheap 500W Garmin in-hull in my last boat and it worked fine for up to 300’ in saltwater. If I end up installing one on this boat it will be 1kW Airmar as you can get the same model transducer with manufacturer-specific input plugs. The higher end Airmar unit have more elements and perform multitudes better than most fishfinder OEM transducers.
I did get a Airmar, it sits in a tank filled with anti- freeze, can't wait to see how it works
 

GradyZ

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Interesting I never really looked into the in-hulls until now and given my use and conditions it may actually be a good fit. I ended up going with a SIMRAD NSS12 EVO3 over the others in part bc it was compatible with the totalscan transom mounted transducer from the lowrance that was also already there.

Contacted Airmar and they identified what is pictured above. Basically if theyre 10 years plus they should be replaced which is the case. Im going to see how the totalscan performs with the SIMRAD before going further. Thanks everyone!