In 1999 a failed drive-train seal caused the drowning deaths of 13 tourists, including three children, when a World War II military surplus amphibious vehicle sank in Lake Hamilton, Arkansas.
Witnesses said that about 7 minutes after entering the water the converted U.S. Army DUKW tilted to the left and then sank stern-first. There were 21 people on board.
One person immediately escaped, but the other passengers and the operator were trapped by the fabric canopy, according to a report by the National Transportation Safety Board.
After the vehicle slipped beneath the surface, six passengers and the operator were able to escape as it descended to the bottom of the 60-foot deep lake.
The agency said the probable cause was uncontrolled flooding due to inadequate maintenance of rubber boots around the vehicle's drive shafts designed to provide watertight integrity.
It also said Coast Guard inspections were inadequate.
And, the agency also said the vehicle had inadequate reserve buoyancy to allow it to float after taking on water.
The vehicle, called a DUKW, is an amphibious landing vehicle that was designed to transport military personnel and supplies for the U.S. Army during World War II, according to the NTSB.
According to the 2002 report, 103 of the vehicles carry one million passengers a year across the United States in cities such as Boston, Seattle and Washington.
The local company said on their web site that vehicles used in Philadelphia are "based on the classic WWII DUKW amphibious design. Today, we build our vehicles from the ground up using the latest in marine design and safety."
It added the vehicles are "regularly inspected, tested & certified by the United States Coast Guard."
Contact Inquirer staff writer Nathan Gorenstein at 215-854-2797 or firstname.lastname@example.org