Replacing transducer- can I use this thru-hull?

[cdhickey]

My current knot meter (analog, probably 30+ years old) is not working and attempts to repair it have failed. I'd like to replace it with a new Raymarine unit, but I'm wondering if I can just add a new transducer to the existing thru-hull, or if I will have to replace the thru-hull as well. Are transducers a standard size and profile?

Pictures of the current gear are below; the old transducer has a diameter of approximately 1 5/8 inches, and the old thru-hull is about 2 1/8 outside diameter. The thru-hull has a small extrusion on the bow side, with a corresponding notch on the transducer.







(These pictures were taken before the boat went in the water this year)

[Alive3and3Well]

The following link provides specs on thru hull opening.

http://www.blueheronmarine.com/files...00_Install.pdf

My Raymarine equipment has Airmar transducer and is referenced from Raymarine website.

Be sure everything is in order and to spec as hull leaks are not fun.

Good luck!

[captainrizzo]

Install your current spedo and take your blank to West Marine. They stock the raymarine replacement transducers and the thru-hull comes with it. They will let you test for proper fit it in the store. Better to see it with your own eyes in my opinion.