fish finder for river fishing?

[Parkerhollow]

Could use some help from you more experienced folks if you have the time?  

I mainly fish the ozark rivers, (G'nade, Meramec, Lower Current, etc.) for smallmouth and usually work in a few trips a year to the lakes and have never really invested much into using a quality locator.  A trip to Bull Shoals a few weeks ago had me wishing for an ability to see what lies beneath and the benefits of sonar on a lake are obvious but what about on the rivers?  Most of what I am fishing is less than 8' deep anyway so I never really bothered with any kind of quality locator.

Would you say there's an advantage to the down imaging and dual beam tech on the rivers?  Or do y'all mainly use them for temp readings and just to get an idea of basic depth in the murkier waters?

Any advice or recommendations on a unit would be appreciated!

[moguy1973]

I have a small down imaging Lowrance unit on my kayak and on the rivers I mainly use it for temp and depth (if I can't already see the bottom)  It does let you see if there are boulders and logs under you if the water isn't clear enough but with the down imaging beam being so narrow and high frequency it really doesn't get much other than what is directly under my kayak at the time.  I can safely say that I have never seen a fish indicated on it.  I think that a regular 2d sonar unit would be better for that.

[Parkerhollow]

Thats really good feedback, thanks for replying.  I honestly had no idea if the beam was wide enough to make it worth having.  

Do the 2D units have a broader angle of coverage?

[Al Agnew]

I use mine mainly in winter fishing.  The most common time when it can be useful is if you are fishing along a bluff bank, assuming stained water where you can't see more than about 4 feet down.  There is a margin where the underwater rocks off the bluff meet the gravel or sand bottom coming from the other side, and I want to know where that margin is, because sometimes it's a good place for deep fish to be holding (and it's an especially attractive zone for river walleye, by the way).  Also, at some point the deep water will begin to shallow as you near the lower part of the pool, and it's nice to know when it shallows to about five feet or so because from there on, your chances of catching winter fish are much less.  It's also useful for finding gravel and sand drop-offs in deep pools, which can also be hotspots for fish in the winter.

However, I often think there is a serious downside to using sonar in a river environment, where the fish are seldom if ever more than 10-15 feet deep and the extent of their "home" is relatively small both in length and width.  You KNOW fish can hear or feel sonar pulses, and I wonder if sometimes the bigger fish are turned off by sonar.  I've started only using it in short periods throughout the day to check water temps or to check the depth of a spot that is unfamiliar to me.

[Seth]

I run an old Humminbird 728 monochrome on the trolling motor and a Humminbird 998 hdsi side imaging unit at the console. I use the console unit a lot when I am on a lake and especially in the spring when I'm after crappie and paddlefish, but rarely ever when I'm on the rivers chasing bass. I'll run the graph on the river sometimes just to keep track of how far I run or if I go exploring new waters so I can mark waypoints and running routes, but that is about it. My transducer stays flipped up and out of the way most of the summer since I am mainly just fishing the rivers so I don't have to worry about breaking a $250 transducer.

[moguy1973]

6 hours ago, Parkerhollow said:

Thats really good feedback, thanks for replying.  I honestly had no idea if the beam was wide enough to make it worth having.  

Do the 2D units have a broader angle of coverage?

2D is more of a cone that is a circle when it hits the bottom.  Downscan is more of a  thin slice of that cone.  Looks like this:

 

The shallower you are the smaller the area of the cone you get also.

[Parkerhollow]

great graphic, makes total sense now.  Thanks for all of the input to all!  I'm looking at a humminbird Pirhanna max 197c that has both the dual beam and the down imaging.  for $150 I think I can justify having it on a boat that gets used 98% on the rivers and 2% on the lakes.  I have had some success with getting a normal transducer to shoot through a .125 hull so I'll see if it can penetrate the .188 so I can mount it on the inside.  Already have the built in transducer in the trolling motor so I can run the unit on a switch.

 I had high hopes of the down imaging helping me finding a few Mitch Craws that get lost on the bottom but looks like I will just have to keep waiting for them to pop up on tackle warehouse!

Thanks again all!

[Flysmallie]

If water temp is important then thru the hull is not going to work. 

[Seth]

I'd just go with the transom transducer and mount it up so the bottom is flush or slightly above the bottom of the boat. About the only way you're going to tear one up mounted like that is if you drift back in to something. You won't be getting any bottom readings while on plane, but I doubt that is much of a concern in a jet boat anyways