Ahhh, but the weight differential increases as the tanks get bigger. A 25 gal polyethylene tank weighs in at 44 pounds (at least according to a Defender Industries listing) while a 25 gal bladder type is still about 6 pounds. I have no idea how big those holding tanks are, but I'm pretty sure they are more than 15 gallons. 36 extra pounds carried well forward is some very serious weight-recall the debate over the stove which is carried much closer to midship and weighs in at only ~12 pounds.
If replacement was permitted, I know I would consider swapping out for the lighter tank setup-I race a bunch of J-29's in PHRF, and weight in the ends is deadly.
