Sidescanning, mapping and GPS are all needed.
[QUOTE=bob46;576762]Been looking to upgrade my lowrance unit I currently have sonar and down imageing I would like to go to side imagining can't hardly find structure with the 4 inch cheap unit. Are the cheaper units like the 7 or the 9 for about 500 worth while for side imagining the problem with spending that much moneyfor a better unit it would be worth more than my boat is worth[/QUOTE]
One needs a basic understanding of structure fishing. And then once that knowledge is obtained one needs to be able to find the structure while out on the water. Knowing the lay of the land and where the structure is located in relastion to your boat is key to catching fish. After that is all about the baits and scents and presentation.
The larger the screen the easier it is to see in the sunlight. Unless you only fish at night the sun will have a huge impact on how you view your screen. So unless you have the type of screen that can be sceen in direct sunlight you will need to think about how to shade your screen so you can see it better. What good is a Sidescanning unit if you can't see whats on the screen clearly. Therefore get a screen that can be seen better in direct sunlight and get the biggest screen you can afford.
You can always remove the electronics from the boat before you sell your boat. No big problem there.
I noticed that with my older Humminbird 898 C SI screen that even when I shade the screen it's hard to see the smaller screen in the daylight. When I record something, take it home and view it on my computer screen which is 23" wide I can see so much more detail than when I was out on the water.
Having a good underwater hydrographic map that accurate and has reliable GPS mapping content is very helpful to finding and fishing structure like drop offs and underwater humps or creek channel bends. Those are all fish holding spots at times and you need to position your boat so that you can present the baits to the fish properly. Fishing parallel to the drop off is better than fishing perpendicular to the drop off. Your bait will stay in the fish catching zone longer with a parallel cast vs the perpenduclar cast. Those things make a huge difference in catching fish.
The best thing that ever happened to fishermen is the GPS and GPS mapping of the lakes we fish. Don't fall for the guy that claims to have 1 ft contour maps when we all know that current GPS units are only accurate to 10 ft or 15 ft 90% of the time. 10% of the time they are much less accurate. GPS signals that have to travel from the satellite to the earth are affected by changes in the Earth's Atmosphere which we can't control. All we can do is adapt to those changes. Having a nearby receiver on the earth with a know position we can check the GPS signals to that location and then send corrections for the errors back up to the Satellite so that it's signals can be corrected for the current conditions in the Earth's Atmosphere. Even then you can only get GPS accuracy to plus or minus 3 ft 90% of the time. There is no way to get 1 ft contours on a map unless you are using 3 surveyors to map the boats postion on the lake. I did that while in school when our class was mapping the muck on the bottom of a lake up at Purdue University. As we took water samples we have a survey crew on the back taking measurements of our boats position for each sample that we took from the lake bottom. This was long before regular people got their hands on retail GPS units.
We so often just throw out what we know and pretend that inaccuracy doesn't exit in GPS units. Maps with 10 ft contours are what I want to see. They give me enough detail to find the creek channels and the sharp drop offs that I like to fish.
Now with side imaging I can not only find these sharp drop offs and creek channel bends near the shorline but I can see if there are other things like stumps or big rocks that hold fish on the drop off. If I can find those objects under the water and mark them on my GPS unit then I can fish them much better. Still it's not always easy to get the boat into position to fish these areas. And if the water is shallow you need to keep the boat far enough away to not spook the fish yet close enough to cast to the fish.