Isolated Structure

Driving along looking at your SI unit you might come across something different (figure 1) to everything around it, often referred to as 'Isolated Structure'. In this article we are going to call it the 'POI' or Point of Interest. When you come across something like this, it's worth putting in the time and effort to really break it down and understand what you are looking at.

Figure 1 (Side Imager)

This little tiger is a school fish, they a very aggressive fish, one will find that they sometimes hit a small inline spinner. They can be found around slipways and any river in an out lets. They tend to move between deep and shallow water so they not really a structure orientated. They can grow up to about 10 cm long.

You will need to do a number of passes and record the POI from a number of angles using your SI 3D. Then do a couple of passes directly above the POI and record it in 2D mode for actual depth accuracy. The other benefit to doing a number of passes is to identify what is fish and what isn't. Humminbird's Fish ID+T in 2D mode, is a really powerful tool for this application.

Once you put this all together you will end up with something like figure 2. You will need to outline the tree using the shadow as a reference.

I always put a scaled image of a person next to it to put it all in perspective. Note the fish, circled in green, holding on this structure.

Figure 2

Once you have all the info and waypoints, put it into Google earth and view it from a slight angle to add a bit of 3D depth. (figure 3)

This is a very unique piece of structure, in this case, as it is very close to a point that has deep water nearby as well as a water run-off / river bed and shallows for baitfish just opposite it. There are other smaller trees around this area as well, but this one seemed to be holding fish whereas the others didn't.

Figure 3

Now comes the question - "How do you fish this 'sweet spot'?" The most common method used is just dropping a marker right on top of it. But what if you don't want to disturb the fish holding on the spot?

Make the base of the tree your target and using your waypoint manager software, create two marker buoy waypoints following the same angle as the little ledge next to the tree, and about 100ft/30m (an average cast distance) from the tree and apart from each other.

Approach your target using your trolling motor from the direction of waypoint 'MB2' (see arrow in figure 4) and drop your markers on the respective MB2 and MB1 positions. Once MB1 is dropped, turn away immediately and allow the area to 'calm'.

Put your boat as close to the marker buoy closest the POI facing into the wind. Decide what to cast at the structure, then cast to the furtherest marker first, just to check on your distance. If you are casting a bit short move your boat slightly closer to compensate, and then cast to your target. Make your 1st cast count!

Fishton
Bassing.co.za Honorary Member

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