Blowsion says the RPR rear fuel tank (5.85 liters) would fit with a few mods, anyone know of a used one for sale. Otherwise I will prob go with the backpack with extra fuel. I can't picture riding with an extra tank in the tray in rough ocean, as it is a proven fact that no matter what time of day it is, the moment I get in the water the wind shifts from offshore to hard southeast. I'm sure BruceSki gets the same conditions in Long Island