not sure ,,,,lol I never go in a straight line ,,,I see a lot of guys will troll along shore staying in one depth ,this is not for me ,,,I troll up and down hill till I find were the fish are, Most times I start shallow and troll toward deep water then I will make a turn and troll back toward shore going shallower ,working my way east with each turn ,My graph looks like a big heart monitor after a day of trolling ..we found fish in 140fow down 75 on the rigger ,so we trolled from 120 to 160 fow and got four good fish ,,we spend the morning working are way east in a S pattern most days starting at the shell pier or just buzzing down to bronte and going east from there ,Things are going to get real good over the next few weeks ,hope to fish all this week weather permitting ,Dutch