Speed could be an issue but a pair of the local guys here that troll more than I do told me that your top dropper shouldn't be more than 8"-10" in length and to use heavier (stiffer) line on the top dropper as well. They got this info staright from Capps & Coleman at a tourney they fished when they were having the same problem. I haven't tried it yet but I do have some rigs tied up with 12# line, 8" long on the top dropper. I use 10# line for the rest of the rig. If the 12# doesn't fix it then I'll go to 15# next. FWIW the guys I got this from fish quite a few tourneys, local & national, trolling so I tend to believe what they say.