I mentioned a couple days ago that ballasting would be critical in keeping this skinny beast right-side up. Well, in my rereading of Ellsworth Kolb's book last night, I found where he too describes the theory:
"Five or six tin and wooden boxes, filled with provisions, went into the large compartments under the stern. A box containing tools and hardware for the inevitable repairs, and the weightier provisions--such as canned milk and canned meats--went in first. This served as ballast for the boats. Then the other provisions followed, the remaining rolls of bedding and tents being squeezed in on top. This compartment, with careful packing,would hols as much as to ordinary-sized trunks, but squeezing it all in through the small hatchway, or opening on top, was not an easy job."
It's just common sense, really--the same concept that makes a punching bag stand back up no matter how many times you knock it down. This concept worked so well in the Powell boats on our 1999 reenactment that in Specter Rapid, after being nearly rolled over by the first big lateral, the boat actuall righted itself as we were being hit by a second lateral from the same side. That was pretty wet. And I think that's where I snapped the 13-foot sweep oar in two.