If you are spotting fish in the depths them than you need a solution to get your bait down to their depths.
An easy solution is owning a Downrigger with a couple of different lead ball weights, these weights will determine how far down and how the bait swims down in the depths. You still want your bait to be presented as natural as possible. We use between a 7lb to 10lb ball to fish between 10 to 16 metres of water. We have also replaced the wire on our downrigger with 200lb Dacron. We have done this to reduce the noise, wire makes a lot of noise when moving through the water and also if you got snagged on a reef you want it to break. It will break more easily than wire.
Placing the downrigger in the starboard side and the rod and reel in the port side. It forms a V shape to the rear of the motor and trolls straight behind the boat. Put your bait on and let some line off the reel say about 10 metres and then clip your ball to the main line off your rod. Using the counter on the downrigger then set the ball at the depth required. You can usually check your depth by checking where the ball is on your depth sounder as per image below:-
Then sit back and wait for the hook up. You may need to adjust the depths depending on where the fish are holding and also because of reef structures etc; it is handy to have an extra angler to constantly adjust your depths for you.
If you don’t have a downrigger all is not lost. Before we owned one we would again let about 10 metres of line out and attach a sinker to the main line with a rubber band and then adjust it to the depth required using your sounder. If you hook up it is usual that the sinker will break off and you can you can continue your fight.
Downrigging is not just for livebaits. We have also used it to troll lures for trout or cod.