@Ohioguy25:
I don’t want to tie up the thread - I can be long-winded. Anyway, I notice you mentioned that you are fishing in a small river so my first question is, “How do you plan to use the fish finder?”
The reason I ask is that if you are trying to see fish in shallow water, good luck! I fish a shallow lake where the average depth is 10 feet. Unless I am drifting, I very seldom mark fish; they just move before I get close enough for the sonar to pick them up - even on the wide setting. @MN Fisher covered that part of the issue very well. My personal experience has taught me that “fish finders” don’t find fish in shallow water if you alert the fish by making any noise such as paddling, rustling around in your tackle, or even casting. It’s actually amazing how much ruckus you create with a hard cast from a yak. But, from my experience, I have learned there IS a good reason for having the Striker Plus 4 aboard.
First, it allows me to “see” where there are even slight contour changes, underwater structures, weed lines, and so forth - even in shallow water. Second, it allows me to set waypoints so I can return to these specific locations. Third, if I find a spot where I catch fish, I can paddle to where I caught them and set a waypoint. And finally, it allows me to produce contour maps of the parts of the lakes where I fish. I just have to remember that each waypoint marks the location to which I want to cast, not where I want to position my yak.
I guess my feeling is that in small, shallow bodies of water, I wouldn’t bother buying a fish finder to actually find fish ... but I would buy it if I want to be able to return to my hot spots on subsequent fishing trips. For me personally that is the value of a fish finder. It sounds like although your water is moving and mine isn’t, we face the same challenges. My thought is that if you use your fish finder as a glorified place marker you will probably put it to good use, but as a tool for actually “seeing” fish, you might be disappointed.
By the way, there is a guy on YouTube known as 1 Cast 1 Fish who has an extensive set of tutorials on the Garmin Striker 4 Series of depth finders. Very informative.
As a final thought, although I mention Garmin there are other fish fibers in the same price range that have similar capabilities. I would recommend that you make sure the unit you buy has GPS and lets you mark waypoints if you want to save locations. Or, if you just want to locate fish, you can pass on the GPS, but will probably not have much luck in less than 15 feet of water unless there is real heavy cover. Oh, and keep in mind that this is anecdotal info based only on what I have learned in the past year. Hope this helps! Let me know if you have any other questions and I will try to answer.