What Is Downrigger Blowback? [Explanation and Charts]
Blowback is the angle or horizontal distance between your downrigger weight and your downrigger. It is created by the resistance of the water to the downrigger weight and line as you pull it through the water behind your boat.
Without blowback, if you have 50ft of line out, you’d expect your bait to be at a depth of 50ft. Due to the resistance mentioned above, the weight will actually rise higher in the water column.
When the speed of the boat is increased or downrigger weight is decreased the horizontal distance behind the boat will increase. This causes the weight to move shallower, so more line needs to be released from the spool to get back to your target depth.
When it comes to trolling, speed and depth are the most critical factors to getting the right presentation and if either is off significantly, it may be a tough day on the water. For example, If you need to troll at higher speeds but want to stay near a specific depth you will need to upsize your downrigger weight or let out more cable.
Downrigger Blowback Calculation Chart
The following charts provide you with approximate blowback data for three sizes of Cannon downrigger weights pulled at three different speeds with no lures attached. The chart also assumes that there is no current in the water.
Water current and direction, water current drag, water salinity, and the use of non-Cannon products will affect your actual trolling depth and blowback. Please use the following charts as an approximate reference.
As an example (1a), the first chart shows that if you are trolling at 4 MPH with an 8-pound weight and you have 100 feet of line in the water with no current; the downrigger Weight is actually at a depth of about 80 feet. The same scenario is shown for 10 and 12lb weights.
Ultimately, there are many variables that can affect where your weight is in the water column while trolling, but the heavier the downrigger weight and the slower your trolling speed, the less blowback you will encounter.
Dial-in Trolling Depth and Blowback
Products such as the Fish Hawk™ X4D, which can wirelessly network with a Cannon Optimum™ downrigger, can provide depth, temperature and speed at your downrigger weight.
This can help take the guesswork out of actual depth and speed at your weight instead of an estimated calculation of blowback.
Learn more about the Fish Hawk system and its connectivity with Cannon Optimum downriggers.
