What are some options for adding an extra 10-20 gallons. I don't want to rip up my boat but is there an alternative to adding saddle tanks on each side. Is the best way to go just carry a couple extra 5 gallons gas cans. Do they make any kind of flexible tanks, ect. Would like to start trolling more this fall but would like having extra fuel if seas got nasty. If I did put something under the floor I'd like to keep it centered, even if it was only an extra 10 gallons.