Marlin transducer flats

[MA208]

Anyone know dimensions of the rear transducer flats on a Marlin? Mine is a 2005 and looking to upgrade over the winter.

Have a big through hull already installed in the forward bilge that I don’t really want to pull out. It died so looking for a different spot.

 

[REBThunderroad]

Did you find out the dimension? I have a 2005 as well. Im looking to install another transducer on teh port side with more power. I run an airmar B744v on starboard side with faring block.- 600Kw it reads at all speeds. Looking for more power and flush mount transducer for the other side. Let me know if you have any advice on a transducer that may work?

 

[Fishtales]

I'm going to say 6" X 10" based on what I recall.

 

[REBThunderroad]

thank you

 

[TortugaBob]

I have a 2005 also, they are big enough for the large 3-3/4" in hull B175 Airmar ducers. I have one on each side 20 deg angle. They are great, hold bottom at speed. 6 x 10 sounds about right.

 

[REBThunderroad]

OK Thank you. I have the smaller b744V holds at all speed but want more power/better read.

So I need 20 degree angle B175 airmar for the flat? Do you remember where you mounted it on the flat - middle, front, etc...? What king of sounder are you using? I appreciate your help.

Rob

 

[MA208]

Thanks, boat is on the hard now and wrapped. I can see the outside dimensions but not internal.

Just for clarity we are talking rear flats for the B175? Not the midship bilge area under the aft bunk?

 

[REBThunderroad]

Yes the rear flats on both sides of the bottom of the boat that GW dedicated for a transducer in their design. However there is a flat inside the bilge as well where the transducer comes through as I recall...and where it bolts up.

 

[drbatts]

Any reason particular reason you don't want to just replace the broken transducer with a new one? Or are you planning on doing that and adding a second transduce?

 

[REBThunderroad]

My B744 works great...it only 600W so I want o add a second that will give me better definition at greater depths. I will just switch back and forth.

I don't want to add another faring block so that's is why I'm looking at the flush mount. I think the 175M may be the one...

 

[MA208]

Same here, I’ve got a big dead transducer and fairing block in my mid bilge area. Don’t want to deal with having it removed as it’s a big hole. I think B 175 in the rear flat is the answer. Going to my Raymarine Axiom

 

[TortugaBob]

Rob, yes, 20 deg, and I believe the Grady Dealer put in the middle. I am running Lowrance HDS Live Units, been very happy with the Navico stuff, but saved a few bucks from Simrad. the 1000 watt will be better, BOE talked me into the High & Wide and it is great B175HW. Depending on your depth of course.

 

[gbgrady208]

I attached the measurement drawing that my dealer made for me on my 2021 Marlin. I ultimately put in the following transducer in the flat and have been happy with the results and how it performs: GARMIN # 010-01966-10 GT51M-TH THRUHULL MOUNT TRANSDUCER

 

[MA208]

Thanks for the drawing. That’s very helpful

 

[REBThunderroad]

Thank you!

 

[REBThunderroad]

Rob, yes, 20 deg, and I believe the Grady Dealer put in the middle. I am running Lowrance HDS Live Units, been very happy with the Navico stuff, but saved a few bucks from Simrad. the 1000 watt will be better, BOE talked me into the High & Wide and it is great B175HW. Depending on your depth of course.

Thank you!

 

[SkunkBoat]

if its a flat, why do you need a 20 degree? I'm confused

 

[SkunkBoat]

Not sure who I'm responding to ...maybe a mix of people

The old B744 is not CHIRP. If you have an old sonar it might not transmit CHIRP so a B175 would be a waste.

Assuming you upgraded the sonar to a modern CHIRP model. B175 is CHIRP which will let you use the features of your sonar. The B175 is a single element transducer.
You could possibly use a B265 or B275 on the flat without a fairing (the fairings are 22" long). They are dual element transducers

If your sonar has sidevu/sidescan feature it will not function without a scanning transducer compatible with your sonar unit. Those are best mounted on the keel (centerline) without a fairing. Mounting them on the flat will block one side of the side scan.

 

[mleads310]

Just for reference if this helps. I replaced a b744 with a b765hl on my 2001 sailfish transducer flat, no fairing (wouldn't fit). The b744 held at all speeds and the b765hl holds till about 30ish maybe 35mph. I also installed a pair of rv220 in the aft bilge connected to my axiom pro.

 

[glacierbaze]

if its a flat, why do you need a 20 degree? I'm confused

Skunk, I think they are flush mounting transducers on a hull with a 20 degree dead rise, therefore they need a 'ducer with a 20 degree tilted element, in order to shoot straight down.