well, thanks for the advice folks, but I made my purchase today. I bought the 31's, I compared the weight of the 31 vs. the 27 and there was only about 10lbs difference and 30$ extra per battery. as much as I troll crankbaits and drift for catfish, I thought I might regret not buying the slightly bigger batteries. now I have all 3 batteries new for the season and ready to go! all I need now is some time off and some water!