Depth Finders

Wiring your boat, How to Wire Lights/Accessories, All things electrical other than actually powering your boat by electric motors.

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mdweber
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Depth Finders

Postby mdweber » Thu Jul 17, 2014 7:58 pm

Hey Folks,

I got a bit bored waiting for epoxy to dry and started to think about electrical systems. I'm thinking to include navigation lights, bilge pump, and depth. I want to keep the boat looking clean, and would prefer not to have a depth finder hanging off my transom. Has anyone had experience with shoot through the hull transducers? I am planning to mount it on the bottom planking near the transom (pretty flat, so I hope it's a good spot). This area is only 1/4" thick.

THanks,
Mike

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jenko
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Re: Depth Finders

Postby jenko » Thu Jul 17, 2014 8:19 pm

I am also interested ,the brochures say the glue in hull is ok on a glass and alloy but not wood ?

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Lowka53
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Re: Depth Finders

Postby Lowka53 » Thu Jul 17, 2014 8:41 pm

:? my humming bird states it can not be place on wooden hull it messes with the signal. it is ok with metal or pure fiberglass you epoxy the transducer to the hull but there can not be any air in the epoxy or the bond :wink: they do make a though hull transducer that is going to need a hole drilled through the bottom :roll:
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mdweber
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Re: Depth Finders

Postby mdweber » Thu Jul 17, 2014 9:18 pm

I got my answer in only 43 minutes...gotta love this forum!!!

That makes a lot of sense, Lowka. I always try to minimize the number of holes I put in my boat, so ill probably end up with a transom unit. Unless there is some other option....

Trackhappy
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Re: Depth Finders

Postby Trackhappy » Thu Jul 17, 2014 9:26 pm

I would maybe cut a hole the size of the transducer and fill the hole with fibreglass flush with the outside, and including some mounting system. The you can put the transducer on that patch. I don't imagine that will cause any issues. Maybe even make it a few inches bigger than the transducer all around just to be sure. Also make sure that you feather the edges so there is like a scarf joint between the glass and the timber for a good strong bond.
That's what I had planned as I don't like the idea of transom mount doodads.

Cheers,
Glenn.

Edit: Just found a thread of someone (on TheWoodenboat forum) who did this and he found it worked perfectly.
By the time I have built a boat, I'll be ready to build a boat....

mdweber
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Re: Depth Finders

Postby mdweber » Thu Jul 17, 2014 9:38 pm

Great idea, track! I'm 30 minutes away from completing the last fill coat on my fiberglass. At this moment I just wanna get the darn thing flipped and start on the deck! I'm going to call garmin or hummingbird tomorrow and ask if there would be any issues with that method.

I'll report back tomorrow!

Also, any ideas on making that bevel? I had an idea of gluing a 4"x4"x3/4" block (or maybe just a 4"x4" plywood block) over where the 'ducer will go, drill out the hull, fill with epoxy, and then pop on the unit.

neel thompson
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Re: Depth Finders

Postby neel thompson » Fri Jul 18, 2014 2:58 am

I installed a thru-hull transducer to power my Garmin GPS/Depth Finder. It creates zero drag and is almost flush with the bottom. It is about an inch and a half in diameter. Works great

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kens
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Re: Depth Finders

Postby kens » Fri Jul 18, 2014 3:03 am

Airmar makes the transducers for all the electronics suppliers.
I used a Airmar B60 with my Furuno sounder.

http://www.airmartechnology.com/2009/pr ... d=36&manf=
Oak is over rated, everything about it takes extra time; then it warps, splits or checks !!! :roll:

mdweber
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Re: Depth Finders

Postby mdweber » Fri Jul 18, 2014 7:29 am

Thanks, Neel and Kens.

Just for the record, is bronze the only material that should be used for thru-hull fittings? I had read that plastic will crack as the wood expands and contracts. I'm not sure about other materials.

neel thompson
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Re: Depth Finders

Postby neel thompson » Fri Jul 18, 2014 8:16 am

Always use bronze in a wood boat. If you use plastic and the wood swells, the plastic could crack.

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kens
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Re: Depth Finders

Postby kens » Fri Jul 18, 2014 7:06 pm

You just have to search the Airmar website, they have so many sizes and types, there is thru hull, and shoot through hull, kinda confusing. then there is plastic, stainless, bronze, streamlined, flush, transom mount, etc., etc.
Oak is over rated, everything about it takes extra time; then it warps, splits or checks !!! :roll:

Trackhappy
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Re: Depth Finders

Postby Trackhappy » Sat Jul 19, 2014 3:27 pm

Cut the hole, use a sander to bevel the edges similar to a scarf. I'd bevel both inside and out, more on the out where most pressure will be exerted. Then cover one side of the hole with plastic cling film and cardboard or something, cut some glass patches and start building the layers into the hole, sticking to normal next layer over green practices. do the other side ensuring you don't leave air gaps. Use glass mat or weave not just thickened epoxy. The only hesitancy I have is the expansion/contraction of the wood versus the glass over time causing a crack, but done right in an encapsulated boat it should not be an issue. We had a 38 foot wooden boat and the professionals did this to repair a rotten area around an old hull fitting so it must be ok. (Where did I red that a professional is somebody who gets paid for it, not necessarily somebody who is good at it?)

The other alternative is to make a hole in the hull with a frame around it (like a small window), and make an insert to take the transducer that screws flush into that window with screws around the outside and an appropriate sealant. With this method you can change it if you need to, and if you remove it you just screw in a blank instead.

All the best.
Glenn.
By the time I have built a boat, I'll be ready to build a boat....


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