I have an Eagle Magna II portable fish finder that I found in the closet that needs a new home.
It runs on 2-6 volt batteries or I think it could be wired direct. I may have the owners manual. I have 2-batteries with it for local pick but can't ship them. Comes with transducer but I can't find mounting bracket. Will keep looking though. They are easily available and there are different options to fit your needs.
I only used this as a depth finder and it was working when I quit using it. I'm taking out to test it later today. Pickup $35/shipped $49