Floating

Today, NPR seemed to be positive about the world. The Pope had changed his image in the US for the better. Two Dutch architects are building floating houses and prisons on water to cope with climate change. The truth about ethanol is emerging. George Bush is celebrating his way out of the White House, having a party with NAFTA this week.
Later in the morning, a co-worker told me about how on her water ski team, they have to tug the big jump they use down river from its storage site to their performance area every spring. So that it won't tip over, they tug it at 3 MPH and require people to sit on it while it's being towed, and they make it into a party every year, bringing beer out and enjoying the three hour trip.
How long can we expect to float?