Transducer location 2011 R21 EC

[Jasper]

Hi guys. I am trying to find the location of the transducer in my 2011 R21 EC. I am currently not able to view depth info. The chartplotter is a Garmin GPSMAP 750s. The previous owner (Tugalong) is unable to offer any assistance, but he did post on here many years ago the he was having problems with the depth showing on the chartplotter and was advised by the factory to move the transducer to a more central position ( whatever that is) and it fixed his problem. I now have that problem. I have no idea as to what type of transducer was installed. So suggestions please to the possible location and transducer type? I have looked under the starboard berth and aft of the engine in the bilge with no luck thus far. I am located in Australia and as you all know, everything is upside down here. 🙂

 

[Catch22]

Assuming you have checked the outside of the hull for any protruding thru hull transducers like Garmin 41 th units. Some people installed these to upgrade . If no thru hulls are found,go online and look for a Garmin GT15 M transducer....it's round and black and most likely what you will be looking for. When you find it, you will most likely notice the liquid inside has leaked out (reseal to hull)or just dried up....a common problem that kills depth readings .Fluids used for refill include RV antifreeze and mineral oil.
Now that you know what it looks like, check the access port just behind the cabin door in the cockpit where the thru hull valve is located. If the intent was to move it more central,it's either there or in the engine dog house forward of the engine to avoid turbulance......good luck....

 

[Jasper]

Thanks Catch22. Well I checked the locations that you suggested but no luck. So then had a look at the wiring harness exiting the chartplotter and noticed a small diameter, of what looked like black coaxial cable, and traced it back down the starboard side aft. The cable was labled "AIRMAR Transducer". It led under the rear lounge seat. I opened up the seat and starboard inspection port and lo and behold, directly underneath, was a AIRMAR P79 in hull transducer. There was a very minimal amount of fluid in the reservoir. The sealing ring was not lubricated. So I will clean the reservoir, replace the fluid (7ml's apparently according to pdf instructions, while a you tube vid installing airmar p70 is way more than this) and see how we go next time out. Many thanks for your assistance Catch22. I should add that in my view the location was anything but more central.

 

[Catch22]

Glad you found it...and yes...anything but more central, eh?
My error on thinking it might be a GM15 TH....that's the CHIRP unit.
The Airmar P79 would have been OEM on most 21s....just not that far aft.
Perhaps they moved the original and did not get a good hull seal.. the liquid loss is likely the issue.

 

[Jasper]

Could be, as it was not glassed in, only silicone. Will drop Tug-A-Long in the water next week and report back. Thanks again Catch22.