So, I've been using the same $50 fish finder on my boat for 10 years. Mainly for a depth finder, since the only time I'm catching kokanee are when I'm not seeing them on the finder. 90% of the time... would like to mark more kokanee when they are under the boat.
Works fine for perch and crappie but not kokes.

What should I buy that will not break the bank account?