one ti ama will support me but not both my girlfriend and me. I would hazard a guess around 250 to 300 pounds.
fill one with water, then measure how much water is in it while pouring it out. That will tell you the volume, which can be used to determine buoyancy and displacement.
KM7, humans are buoyant, and in the water we only require about 20lbs of floatation.
If my mammary serves me well, I think that women require slightly less.
I should have been more specific. When standing on my haka, which is directly over the ama, it floats. If there are two of us, we sink. It is likely that the other ama and haka were counter balancing the one we were standing on but I would estimate around 250 to 300 pounds of floatation. We didn't sink very fast...