To fully appreciate the advantages of different shotting patterns, it is important to consider how current flows through rivers. A typical cross section of river will have a number of different currents flowing together. In general, the slowest current will be at the bottom and edges of the river and the fastest current will flow at the top and middle of the river. These variances in current speed can be seen when watching autumn leaves flow downstream. The leaves on the water's surface travel much faster than those caught along the edges and in underwater currents.
Proper shotting allows the line cut through the faster surface current and the bait to drift at the speed of the slower bottom current, ahead of the split shot and float. Whenever shotting a float, it is essential to use good quality round shots to avoid line twist under the float.
As a final thought to keep in mind regarding shotting patterns, try using a variety of shotting patterns for every pool or run. Each pattern presents the bait differently, allowing it to catch different underwater currents and cover different depths. Covering these different holding areas within a pool or run will maximize the catch out of any spot.
Standard Shotting Pattern
The shots are equally spaced on the line, from below the float down to the swivel and leader. Typically, the shots taper in size from the largest, directly below the float, to the smallest just above the swivel. When this set-up is running through the water, the bait will drift naturally ahead of the float and the line will curve smoothly upwards to the float.
Some anglers will substitute several smaller shots stacked side by side, rather than using a single larger split shot. For example using 4 no.4 shots (4x.20g) to replace 1 AAA shot (.80g). This allows them more flexibility when sliding shots around from one set-up to another and tends to present set-ups with slightly more finesse. As an added bonus, anglers can get away with a smaller variety of shots in their vest. Stacked shot set-ups should be prepared in advance on a shot line to reduce downtime while fishing.
This shotting pattern allows for a longer tapered presentation between the float and the bait. The spacing between the shots increase as the size of the shot decreases down the line. This pattern offers a very natural free-drifting presentation, but is relatively slow to sink down to depth. It is ideal for use in slow pools and clear water, but not recommended for use in fast or deep runs.
This is basically the inverse of the tapered shotting pattern. The shots are spaced closer together as they run down the line. The basic idea of presenting a tapered curving line towards the fish remains the same, but most of the weight is placed down near the leader. This pattern efficiently cuts through the surface current and pulls the bait down to depth quickly. Accelerated shotting is perfect for faster runs and deeper pools.
Bulk shotting is the most effective way to cut through current and get the bait down to depth quickly. All the shots are stacked just above the leader with the last few shots spread out slightly to offer a more tapered presentation. This set-up may hinder the natural presentation of the bait, but is sometimes the only useful pattern in fast deep water.
Shallow Water Shotting
In shallow water where fish may be easily spooked, use this pattern with a small float and light lines. Load the shot directly below the float and space a few smaller shot along the line above the leader. This pattern is ideal for fishing shallow pools and runs where there isn't enough depth for a useful length of line under the float.
When fishing in very fast water, over-shotting is sometimes the only way to break through the rushing surface water and still present the bait at a natural speed. This set-up is the same as bulk shotting, but extra shots are added to the line (as much as twice the regular carrying capacity of the float can be used). The float will sink completely under the weight of the shots. Hold the float back firmly so that the force of the current pushes the float to the surface. Then allow the float to trot downstream at a pace that keeps it kiting just on the surface. By adjusting the length of the line under the float and the amount of weight, the bait can be run at a fairly slow pace through fast runs, allowing it to catch slower underwater currents. Because there is no slack line between the float and rod tip, strikes will register directly on the rod.
In very large and deep rivers, bulk shotting and overshotting may still not be enough to hold the bait down to the bottom. By using a three way swivel with first eye tied to a short leader down to a pencil weight, the second eye running the main leader to the hook and the third eye is attached to the main line up to to the float. This rigging pattern is used extensively in the Pacific Northwest.
When river fishing in windy conditions it is often difficult to control the float, as the line is constantly dragging the float around. In this situation, "back shotting" gives the angler some much needed help. Simply add a small split shot 6"-12"+ above the float to bury the line under the surface of the water. This helps reduce the effect of the wind on the line and float.