Sink depth of trolled fishing lines

During recreational troll fishing, success usually depends on the ability to maintain the lure at the desired depth. When trolling with a heavy line, one whose inherent density sinks the lure, depth control is guesswork for most anglers. This study presents a method for predicting the trolling depth of heavy fishing lines. The model is developed based on the fluid mechanics of the line being towed through quiescent water and determines line depth for known line properties and trolling speed. Experiments are performed to validate the model and results are consistent with the model predictions. The model is employed to illustrate how trolling depth can be controlled during typical fishing situations.