Airmar B175 Transducer Installation

s_explore

Seaman
Joined
Oct 15, 2021
Messages
54
Hi everyone,

I'm installation the Airmar B175 in my boat. My boat has a core of balsa between the inner and outer layers of fiberglass. From the Airmar instruction, they say to drill the first hole of 95mm which I did. The transducer fits correctly in the hole. Now their instruction say to drill a 6inch hole from the inside through the inner layers of fiberglass and the core. I don't want to do that, my inner fiberglass layer is thick I rather to keep it for solidity.

What I am thinking is scrapping the balsa core with a screwdriver or something then adding resin and then thickened resin to fill the balsa I removed. Did anyone did the same? I added a picture of my hole to let you see.

Another question is did anyone install the transducer in the engine compartment. They say to not install it there, but this was my only option. I am thinking to add two 12Volts fan to blow directly on the transducer to help it cool down.

Thanks for the help,
Sam
 

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dingbat

Supreme Mariner
Joined
Nov 20, 2001
Messages
16,066
Hi everyone,

I'm installation the Airmar B175 in my boat. My boat has a core of balsa between the inner and outer layers of fiberglass. From the Airmar instruction, they say to drill the first hole of 95mm which I did. The transducer fits correctly in the hole. Now their instruction say to drill a 6inch hole from the inside through the inner layers of fiberglass and the core. I don't want to do that, my inner fiberglass layer is thick I rather to keep it for solidity.

What I am thinking is scrapping the balsa core with a screwdriver or something then adding resin and then thickened resin to fill the balsa I removed. Did anyone did the same? I added a picture of my hole to let you see.

Another question is did anyone install the transducer in the engine compartment. They say to not install it there, but this was my only option. I am thinking to add two 12Volts fan to blow directly on the transducer to help it cool down.

Thanks for the help,
Sam
I installed the same transducer in my boat.
My hull is solid glass, so didn't pay attention to the cored hull instructions.

Looking at the installation instructions, I don't see why you couldn't use a Dremal to cut the core back say 1/2" then fill with epoxy to seal the core.

The transducer is housed in a brass housing in full contact with water. If the transducer gets hot enough to affect performance, you have bigger problems to worry about.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
Jul 23, 2011
Messages
49,534
I use a bent allen key chucked in a drill to remove a bit of balsa core. that way the fiberglass acts as a guide, and the allen key chews out the core to a fixed depth.

then mix up some PB (see the stickies) and fill the void. dress as needed and it will be a solid bit around the transducer hole.
 

s_explore

Seaman
Joined
Oct 15, 2021
Messages
54
Hello guys,

I have proceed exactly like that and I think the job is really good I'm happy with the result. Now time to put the engine in and go test this.

Have a great day
 

cyclops222

Lieutenant
Joined
Mar 21, 2024
Messages
1,289
I have always put any holes in a bottom area that is open & easy to work on. I do not need to find fish or get a shallow alarm. While on a full planning speed.
Replacement bottom pumps are also in a easy to work on area. Usually right next to the transom area. Close to the center line.. I never try to remove old bottom pumps. Just remove the pump wires & extend with self sealing ..Butt Splices on to pump leads held above expected high water levels.
 

dingbat

Supreme Mariner
Joined
Nov 20, 2001
Messages
16,066
I have always put any holes in a bottom area that is open & easy to work on. I do not need to find fish or get a shallow alarm. While on a full planning speed.
Replacement bottom pumps are also in a easy to work on area. Usually right next to the transom area. Close to the center line..
You can put an intake on center line with a single engine installation but you run the risk of prop cavitation.

In my case, I have two water intakes, a thru hull transducer and a side scan transducer mounted on the transom. On top of that, had to make sure they all cleared the support structure on the trailer as well.

All "accessible" (tongue in cheek) through a single, 8" diameter deck plate...lol
 
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