There are a lot of variables in that question. What are you going to do with it? Do you want 2D and down imaging, and or side imaging? What kind of money do you want to spend? Even though I have not used a sonar in several years I owned more than one and used them regularly a few years back. After more than a year of being on the fence I made my purchase....a Humminbird 899ci HD SI. That is a big sonar for a kayak. But the more I read and the more I looked at videos on youtube I took the advice of many on sonar forums. If you want a sonar with either side imaging or down imaging...or both....buy the biggest screen size you can afford then up the purchase even more until it hurts. That is what I did. I am mid 60's and my eyes are OK but no way could I make out all all that would be shown in the image on a si or di with those small screens. I had a specific goal that I wanted my sonar to do.....find bluegill beds in deep water....find structure...and then use 2d to see if any fish are on that structure....even though you can see fish in the si and di it is much easier to see fish on a 2d sonar. Also to have GPS to mark those spots once I find them and can go right back to them. I am in the hunt for trophy Gills in deep water...I am also going to use it in the middle of summer to find Gills when they move into the deeper water and you can't just fish the shore line and catch them as you can in spring. I got tired of fishing in the middle of summer and fishing blind in the lakes I fish. I posed this question to several members on here and all of them told me the same thing about the size of the screen for si and di.....get as big as you can get. Believe me I did not want to spend the money that the 899 costs...even though I got it at cost....it still hurt. But after deciding what I really wanted to do with a sonar I knew that if I got anything less I would be very disappointed and I did not not want to have to buy again. I know as well as anyone that it always comes down to money but I would have to say no matter what you buy it will be better than fishing blind. Even the cheaper 2d sonars they make today are light years ahead of what they had 10 years ago.
If you are going to use a it quite a bit, I would really recommend one with a gps. If you fish a lot it really can help get you back on the spots that you want to fish. If you are only going to fish 5-10 times a year I would just get a low end depthfinder with a temperature gauge.
I go often from spring to fall. I have a budget of only about $300. I want to be able to see structure just as you stated Alpha. I want to be able to find fish when the summer heat comes and the shallow water isn't producing.
Academy did have a few of the Lowrance Elite 4 series on sale but I don't know if any are left. They were getting rid of last years model. Those units are good for the money.
Electronics for Kayak
