This right now is looking like a good deal. 3 days left on the auction but right now its 300 and some change. If the rolled alluminum sections are 4 feet then that would put these around the 24 foot plus. These would make a great floating blind. You can set the width to whatever you want as they are just pontoons.

http://www.publicsurplus.com/sms/all,tx/auction/view?auc=1695179