On American passenger ships, expanding waistlines are lowering hull lines, forcing the authorities into action.
The US Coast Guard has raised its average passenger weight from 160lb to 185lb – an increase of almost two stone. It is the first time it has done so since the 1960s.
That the average American is a touch portlier than 50 years ago may not come as a huge surprise but it is a blow to many commercial boat operators, who will be forced to reduce capacity.
"People have just gotten heavier," said Coast Guard spokeswoman Lisa Novak.
The Coast Guard has followed the lead of other transport administration bodies. The Federal Transit Administration, with responsibility for the nation's buses, still tests vehicles as if the average rider weighs 150lb – it has just proposed a jump to 175lb. Prompted by a 2003 plane crash in North Carolina, the Federal Aviation Administration has raised its average weight estimate from 170lb to near 190lb.
Ashes on the Sea, a California based company that conducts ocean burials, is concerned the new rules will force them to raise prices. Anticipating less usable space on many of the 50 boats he charters in five states, Ken Shortridge, from the company, said the change could add several hundred dollars to the cost of each service.
"Unfortunately, the new rule makes sense," he said. Overloaded boats are more likely to capsize.
In 2004, a water taxi called the Lady D flipped over in Baltimore harbour, resulting in the death of five passengers. A year-long investigation followed focusing on outdated estimates of passenger weight.
Not all services will be affected however. Catalina Express, which annually ferries hundreds of thousands of passengers from Los Angeles to nearby Santa Catalina Island, won't be carrying any fewer.
"It won't affect us at all," said spokeswoman Elaine Vaughan. "We usually carry less than our Coast Guard-approved capacity. That's a decision we made for comfort reasons."
The new boat rule takes effect in December, after the 185lb figure was first suggested in 2006. Since then, the average American has already grown a couple of pounds heavier.Reuse content