Re: Speaking of Meaningless Comparison Measures ...
If you shape the pool carefully enough, a thimbleful of water would be sufficient to float it in*. I guess that a thimble is about 0.0043 Bulgarian Airbags or approximately 0.000000001 Olympic-sized swimming pools.
If you really wanted to push the boat out, you could easily manage to float it in the volume of a British Standard Egg Cup (a defunct official British measure that predated elReg standards by a few decades).
*I assumed that I could use a massive, but precise, 3D printer to create a boat shaped pool around it.