This design utilizes a “pontoon style” assembly of the barrels which is the most efficient way to maximize floatation and minimize drag. To offset the weight of our shelter, we would fill the barrels on the opposite end with water. Since each barrel has a maximum buoyancy of ~450lbs. and a 20ft raft would have about 6 barrels per pontoon, we would have an absolute maximum raft weight of 5400lbs. Given the weight of pressure treated lumber, I cant imagine our raft could weigh more than 2500lbs (without gear)