replacing depth guage in 08 AR210?

[MacAR210]

Anyone replaced their depth guage? My stock one shows a reading when the boat comes on, but then flashes to a few dash marks across the screen like it cant read the signal. Would like to keep the stock one but just a new Yamaha OEM transducer is way more than say a hummingbird in-dash with new transducer. Does anyone know for sure the size of the stock guage? Just looking to get a direct drop in replacement. Thanks

 

[RumDiet]

Haven't yet but I want to add a fishfinder - so will have to add a transducer for that - looking to see if anyone has done something similar. I want to use a transducer that mounts in the bilge so I don't have to drill a hole in the boat or have something hanging off the transom. From my experience if you change the gauge to Hummingbird or something similar you will have to also change out the transducer.