P79 Transducer question - R27

TugScout

Well-known member
Joined
Aug 12, 2018
Messages
153
Fluid Motion Model
C-24 C
Non-Fluid Motion Model
Nordic Tug NT32-220
Vessel Name
Polaris
Hi Gang,

For those of you with an intimate knowledge of the P79 transducer, could you please take a look at the photos in my album and tell me if it looks like the transducer is actually in the glycol cup or if it is just glued to the hull.

The cup in the P79 installation manual looks much larger and has a flange on the bottom, but I'm thinking it could be all buried in resin. I know there were reports of the transducers being glued directly to the hull so I was hoping someone here could tell from the pictures.

Now that I've located it, I'm going to need a 12-18" orthopedic extension to actually reach the dang thing.

Thanks,
Mark
 
Glued directly to the hull.
 
German makes a p79 without the cup that was used by fluid motions on a number of there models, on my R-21 2009 the p-79 was glued to the hull, this is the same transducer that is sold for elect. Trowling motors by Garmin. Your pictures look just like what I had prior to my replacement to a through hull . See my photo album for the upgrade. Bob
 
Yep, glued down. I dread the day I have to fix mine. I am looking for a spot that will be easier access where I can install a new one when needed. The real estate seems scarce.
 
Thanks everyone. I had thought it was likely glued down as well.

So has anyone found a better, more accessible location for a replacement?

Many thanks,
Mark


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I just repaired mine on a CW 28. iMarineUSA.com sells just the replacement cup and o-ring for $19.90.
I used a dremel tool with a small flap wheel abrasive to grind the putty from the hull. You have to be careful (hand scrapped) when cleaning the P79 transducer of any residual mounting putty. Use some 5200 or equivalent to remount the new flange and you should be good. Wear your knee pads and bring a small vac.
Jeff
 
There is a small space under heater beneath the helm. I installed a transducer, glued to the hull with an angle spacer to make it level. I wanted a second transducer that was more forward so I would get a slightly earlier warning about shallow waters. I also installed a second depth sounder screen above the helm console.
 
ALICE J":3f1dqtcw said:
There is a small space under heater beneath the helm.

Thanks! I will poke around in that area when I'm down at the boat today.

Cheers,
Mark
 
Cutwater28GG":3ryzhpxq said:
whilst its a cutwater 28 you might find some of the photos useful http://www.tugnuts.com/viewtopic.php?f=5&t=11272&hilit=sonar

Thanks! Nice installation. The first thing I noticed was how accessible the transducer is on your C-28. The access for mine is through the rear seat after removing the shelf the propane tank sits on. The reach is about 30" to get to the dang thing, much less actually work on it.

Cheers,
Mark
 
Jeff58":3vilg4cw said:
I just repaired mine on a CW 28. iMarineUSA.com sells just the replacement cup and o-ring for $19.90...
My sounder has been getting progressively worse at losing the bottom over the course of this season so decided to check the fluid in the cup. Imagine my surprise when I discovered that Fluid Motion chucked the cup and plopped the transducer down on the hull with some caulking under it. Wondering whose brilliant idea that was. As much as I love the design of these boats and as impressive as the customer service is sometimes I wonder at the things that are done in the factory.

Thanks for the info on the source for purchasing just the cup.
 
Just a note: the Garman P-79 transducer is a entry level transducer! It is the least expensive one that Garman sells, there is a reason for that! As your unit is only as good as the transducer your using , just ask any USN Sonarman, which can usually be found at any waterfront bar! A in hull transducer has to transmit through the hull and losses signal strength depending oh hull thickness, for the P-79 that thickness is no more than 5/8 in, which most Ranger Tugs, and Cutwater boats will be borderline if not over. Most boat owners will not have any issues with the Garman P-79, however don't expect it to last or perform as the higher quality ones! For more info about this subject check out the Garman Transducer Selection Guide.
And I agree that if I was spending the money that a new boat cost I would expect that the equipment installed was of quality, and not the least expensive!
 
When installed properly in the cutwater though the p79 can still hold the bottom down to 800 feet and see salmon trails. Yes it is not a side vu or a panoptix sonar but honestly even if cheap it’s not bad for most use cases.
 
yep
but to be fair I bet ranger customer service gets less queries than if they had installed with the cup. the cup is very prone to leaks through the gasket which would probably have driven a bunch of questions too.
 
for those of your that have the cup installed? anybody stopped it from leaking? I have the gasket in the right location but in rough conditions it definitely loses some glycol
 
If your cup is glued with 5200 or 4200 check if the glue actually is holding al around. I discovered that small amounts of steering fluid collecting in that compartment on my r27 weakens the bond of the cup adhesive and thus caused leaking of the fluid in the cup
 
Cutwater28GG":hnato97a said:
for those of your that have the cup installed? anybody stopped it from leaking? I have the gasket in the right location but in rough conditions it definitely loses some glycol

Originally the cup leaked. Two issues found from factory installation, missing o-ring and broken tab or boss on locking ring. After replacing the locking ring and installing an o-ring, filling the cup with propylene glycol. I haven't added a drop. 3 1/2 seasons of use. Put a liberal amount of Vaseline on the o-ring before sliding it on the transducer. This will help seal the transducer and cup and prevent the fluid from leaking.
 
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