Deep Finder Airmar 79 Fluid

A

allanrs74@gmail.com

Well-known member
Joined
Mar 1, 2018
Messages
109
Fluid Motion Model
C-28
Vessel Name
Cherokee Rose
On my last trip out, my deep finder stopped working. I’ve learned from this forum to check the transducer housing for fluid. And as others have found it was almost empty. I filled it with RV antifreeze and it looks like it holds a level about 1/2” from the top rim. From reading Tugnuts posts and the manufacturer’s manual, it looks like the cup should hold fluid all the way to the top rim. Could anyone confirm if in fact the Airmar 79 transducer cup should be filled to the top rim? I could have a cracked case?
Thanks for your assistance.
Bob Allan R-27C
 
I have found that as long as the glass stays covered with fluid, the reads are solid. Glass not fully covered with rocking?.......no readings or inconsistent readings.

Official answer? Dunno.
 
The cup should be full. When I fill the cup I fill it about 1/2 full. I then take paper towels and wrap all the way around the cup to catch the overfill spill. As is install the transducer the fluid starts to spill over the top as I push it down. Slowly pushing it down so the fluid is displaced by the transducer. I let it leak out around the rim of the cup for a few moments before doing the final locking of the transducer to the cup. The paper towels are usually soaked but collected all unused antifreeze. I do a final cleanup and now I know I have a full cup.
 
Thanks for the information. Like many other posts on this subject, I found no o-ring on the transducer cup cap. I’ve refilled the cup and screwed the cap on again while I wait for delivery of an o-ring. I’ll test it the next time I’m in the water.
Regardsu
 
allanrs74@gmail.com":26curdtc said:
Thanks for the information. Like many other posts on this subject, I found no o-ring on the transducer cup cap. I’ve refilled the cup and screwed the cap on again while I wait for delivery of an o-ring. I’ll test it the next time I’m in the water.
Regardsu
Click to expand...

I would assume that after all the installs that Fluid Motion did and all the threads about the missing o-ring on TugNuts it is no longer an issue. 2015 to 2017 Tugs and Cuts I know were missing O-rings.

I troubleshot a Garmin depth reading issue on a Ranger R25 2016 in 2020. The owner took delivery of the Tug from the factory. The depth sounder was not working properly then. The Ranger folks told him they checked it out and they felt the Garmin 7612 needed an update. He didn't know how to do the update at the time so he cruised around in the PNW for a couple of months with it working erratically. Before he left the PNW he had the factory fix a few warranty items and they fixed the issue with the depth reading before leaving the PNW and heading east. From that point forward to 2020 he thought that his depth sounder was reading as good as it could which was not very good. He was on my boat and he noticed how I was getting a constant reading of depth. He commented on it and I responded "that's how they read". "Not mine I need to figure out how to do an update!!" We went on board his boat and I searched for the transducer. It was located in the far aft section of the starboard storage locker under the deck. When I removed the transducer from the cup it was bone dry and had boat build fiberglass dust laying on the bottom. It was bone dry!. There also was no O-ring. I had this issue the day I took delivery of my 2016 C26 and was told by the dealer that's how they all read!!! I didn't buy that answer and looked into the install and found the same issue as I found in my friends R25, dry and no o-ring. I ordered a couple extra orings at the time. I had an extra still on board so I installed the o-ring and we filled the cup with water (we didn't have antifreeze at the time and wanted to confirm that this was the fix. After installing the o-ring and filling with water the R25 owner was smiling from ear to ear!!!" It has never read a depth constantly like that!!" He had Many miles of water under his keel with no Depth sounder!!! At that time he had just over 1200 hours on the engine. A boat builder can build the best boat there is, but it is the little Quality control items and service that leave the long lasting impression on the over all Quality of the boat. I was told by a VP of Fluid Motion they have really stepped up on Quality Control and products they use over the last few years. Cudos to them if they did!
 
My Airmar cup has separated from the deck (2015 R-29). Over the years I’ve had to refill the cup two or three times; I’m assuming that twisting the cap off and on several times has loosened the cup from the sealant/bonding agent and it has finally broken free. My questions are these — after cleaning the remaining sealant from the deck, how much sanding, if any, of the deck surface should be done? Should it be sanded perfectly smooth, or will a rough sanding suffice? And what sealant/bonding agent should be used to secure the cup to the deck surface?

Gordon
 
Gordon, If you are going to do an install the same way the factory did follow that video, Most of the work has already been done and all you have to do is make sure you have two good clean surfaces. Use a good marine Sealant, boat life marine Silicone rubber, 3M 4200, or 3M 5200. The advantage of the silicone is it dries fast. The disadvantage is it is third on the list as best adhesive products. (1) 5200 (2) 4200 (3) silicone. An extra step that I do when glueing the cup to the hull is I have several cut pieces of masking tape ready before attaching the cup to the clean hull. I apply the sealant to the cup and lightly push the cup down. I then use the masking tape to hold the cup in place so it does not slide down the hull dead rise. Tape lightly this is not for compression it is just to hold the transducer in place. When the sealant is cured remove the tape. The cleaner and smoother the cup to hull mating surface is the better adhesion and seal will be. I recommend using 80 grit paper for a better etching and stick. Use alcohol instead of acetone for the cleaning and degreasing. Good luck on the repair.
 
Thanks, just what I needed!

Gordon
 
I had intermittent readings and changed the cup after finding it cracked and leaking. The transducer still did not work. So then after being told that the transducer may have burned up by it running dry in the cup, I replaced the transducer. I still had intermittent readings. I finally gave up and installed a new transducer, not a through-hull but an actual through hull (hole through the hull) and the transducer is now flush with the under side of the hull. Cost a few bucks but it works great.
 
Spoke too soon. Does anyone (maybe the factory) happen to know the deadrise angle for the R-29? Since the cup has become detached from the hull, I need to reinstall. I could measure it, but it’s hard to do while hanging upside down.

Gordon
 
Gordon, I found the easiest way to find the dead rise for the area you wish to attach the transducer is to use the measure app on a smart phone (level), it's as easy as dropping your phone in the bilge, big numbers easy to read. Hope this helps! Bob
 
Thanks, Bob. I actually didn’t know my phone had a level app. I see now that it has a surface level option. I’ll give it a try!

Gordon
 
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