Fish finder transducer question

[dvan1901]

I would like to put a fish finder on my boat, but don't want to drill through the hull or mount it on the transom. What are my options for using a transducer that can be mounted in, say the engine compartment, and shoot through the hull without having to be drilled? Anyone run this configuration with success?

 

[rndn]

Re: Fish finder transducer question

The thru-hall transducers are not as good as the transom mounted versions. After the first hole it gets easier to drill the other two. Make sure you chamfer the edges of the holes if you're drilling into fiberglass. It will help to stop it from cracking. make sure you use a good marine grade sealant. Only marine grade will do as it expands slightly when it cures.

 

[lncovert]

Re: Fish finder transducer question

Small piece of advice. If you mount it on the transom, keep it away from directly beneath the scupper drain holes. If any fuel drips out of these holes it will deteriorate the transducer mount. I had no idea it would do this and I also had no idea that fuel was sometimes dripping out of the scupper hole. My first transducer ripped off in the lake because the fuel had deteriorated the transducer mount. I thought it was just old, so I bought a new one and put it in the same place and it also deteriorated within 2 months.

 

[dvan1901]

Re: Fish finder transducer question

So my boat isn't a fishing boat, it's a deck boat that I happen to fish out of every once in a while. Because of this, I don't want to mount one on the transom if I can avoid it. I was kind of researching fish finder transducers and came acrros these "in-hull", not the "thu-hull". I think I would rather do that if it seems to be good enough for casual fishing now and then. Most of my fishing would be spoon jigging, crank baits, Carolina rig fishing. The fish finder would be mostly for finding fish for spoon jigging.

 

[wire2]

Re: Fish finder transducer question

I've had a Lowrance flasher type of depth/fish finder in my boat and put the transducer on a blob of epoxy resin, on the bilge floor.

It worked just fine.

Keep it level until the resin cures.

 

[dvan1901]

Re: Fish finder transducer question

Wire2, do you happen to have a link to the type you have?

 

[wire2]

Re: Fish finder transducer question

Wire2, do you happen to have a link to the type you have?

Not likely, I bought that one in 1975.

But the transducer is like a small hockey puck, 1?" dia. or so, with a wire out of it.
The indicator is a spinning dial with a neon lamp that flashes at the number of feet marked on the scale.
Crude but it works.

It started to hum, was a bit out of balance so I replaced it with a Humminbird Wide Eye.

 

[mandopickr]

Re: Fish finder transducer question

An inhull transducer can provide as good a resolution as a transom mounted transducer, depending on your hull type, and transducer type. Its an easy install, you'll find several postings on this and other sites that tell you how.
You can only install inhull with a solid, not sandwich, hull. Tri-beam tranducers didn't perform as well for me on the exterior beams. I couldn't detect any loss of signal when using a standard transucer.

Test for the proper position, use slow setting epoxy, and you should be pleased with the results.

 

[wire2]

Re: Fish finder transducer question

You have to have no air between the transducer and the hull, even for a test. You can use either grease or Vaseline to try a location, then epoxy at a good spot.

 

[dvan1901]

Re: Fish finder transducer question

I've read about the no air and solid fiberglass. My boat manufacturer lists the hull layup schedule; what do you think, should work right? No wood here:
1. Layer 18oz woven roven
2. Layer of strand mat
3. Layer 18oz woven roven
4. 1-1/2 oz skin coat
5. 25-30mil polyester gel coat

 

[wire2]

Re: Fish finder transducer question

Yes, will be fine.

 

[bassman284]

Re: Fish finder transducer question

When I bought my boat the dealer glued a block of nylon to the bottom of the transom and ran the screws into that. Haven't been successful in a google search so far but I bet a dealer service manager could tell you what they use.

 

[bassman284]

Re: Fish finder transducer question

OK, found it. they are acutally made of HDPE. don't think I can post a link because of the competition thing although I could not find this product on iboats.

If you Google transducer mounting plate you will see what I'm talking about.

Now all the sources there show the mounting plate itself being mounted to the transom with screws. My dealer used some kind of adhesive and it's been good for six years so far.

Let me know what you think.

 

[dvan1901]

Re: Fish finder transducer question

Now that is interesting bassman; I found what you are talking about and it seems if you used a good marine adhesive, rated for underwater use, that would last a long time and be solid. I may have to look into doing that; great idea, thanks!

 

[bassman284]

Re: Fish finder transducer question

Now that is interesting bassman; I found what you are talking about and it seems if you used a good marine adhesive, rated for underwater use, that would last a long time and be solid. I may have to look into doing that; great idea, thanks!

Another thread on here names the adhesive: 3M 5200 marine adhesive. See link.

http://forums.iboats.com/showthread.php?t=224629