Hobie recommends storing the PA flat on it's bottom, or standing it on it's end (rear handle). When I bought my PA the dealer told me not to store, and/or transport the PA upside down or on its side because factors such as heat and its weight can cause the PA to warp or become dented. My PA was dented once from a long transport via truck top sitting on land shark mounts when the sun was full and the temps were high, but after being in the water they disappeared and the hull returned to its original condition. I was told this is normal, but if my PA had been seated on those mounts for a long period of time (days or weeks?) the polyethylene (PA's hull material) would have remained dented and not return to normal. Kind of like the hull material has a short-term memory