The "ducks" as the World War II era amphibious vehicles are popularly called, aren't quite a boat or a truck, and many aren't from the 1940s, either.
That complicated heritage has produced a complicated web of agencies that regulate these floating vehicles, a popular and familiar tourist attraction in Philadelphia since 2003.
The "Ride the Ducks" operation, owned by an entertainment company based outside Atlanta, Ga., is regulated on various levels by city, state and federal authorities.
The city oversees its business operations, the state regulates the vehicles on streets and highways, and operations on the water are overseen by the Coast Guard, which inspects the amphibious vehicles for safety and compliance.
That oversight has not been without controversy. A 1999 sinking that killed 13 people on Lake Hamilton in Arkansas, was blamed on lax Coast Guard inspections that failed to catch a faulty seal.
A subsequent National Transportation Safety Board investigation produced a lengthy list of recommended changes for the hybrid vehicles, which were originally designed to transport troops in World War II and were called DUKWs.
The recommendations included adding flotation to keep the vessels above the water if flooded and modifying the canopy. Used to shield riders from the sun and rain, investigators found that the canopy impeded passengers attempting to escape.
The 1999 investigation involved a World War II era vehicle. The construction date of the vehicle at the bottom of the Delaware River could not be provided by the Coast Guard yesterday. A spokeswoman for the company described it as a "refurbished" 1940s vehicle.
Much remains unknown about Wednesday's accident. Witnesses said the boat, with its trademark canopy, sank after being struck.
The NTSB report on the 1999 incident said "the major consideration in assessing the ability of passengers to escape from a sinking DUKW is the overhead canopy." It is not known if the canopy was a factor here.
The safety board wrote that the "major consideration" is passenger safety. As a vessel sinks, the natural buoyancy of a human body can entangle it in a canopy, which can impede escape.
The most recent Coast Guard rules say "canopy supports should be positioned to allow the majority of passengers unobstructed egress."
Another major issued cited by the NTSB is "reserve buoyancy." That is the ability of a small vessel to float even when partially filled with water. The ducks of all vintages are not required to add flotation.
On its website, Ride the Ducks says its amphibious trucks may look like the World War II vehicles, but that, "Today, we build our vehicles from the ground up using the latest in marine design and safety."
The website adds: "Our newest model, the "Truck Duck," has been approved by the USCG Marine Safety Center for "Partially Protected Water" routes."
Sharla Feldscher, a public relations representative speaking for the company, the vessels are inspected yearly before the beginning of the season in March.
Coast Guard regulations covering "small passenger vessels" apply in this instance and grant inspectors wide latitude to "accept alternate" arrangements because of the many variable designs of vessels on the water.
For example, the amphibious vehicles are not expected to have the stability of a vessel exposed to large waves and storms.
When on land, the vehicles are regulated by the city. The Streets Department issued the company a one-year tour operator's license and loading-zone permits in March 2010. The Licenses & Inspections Department also issued a business privilege license to the entity that officially operates the vessels, Penn Ducks, in October 2006. That entity has paid all fees and taxes related to that license, according to mayoral spokesperson Maura Kennedy.
The duck boat company is also required to submit traffic safety reports each year to the Streets Department. Those records, which typically record vehicle accidents on city streets, were not immediately available Wednesday.
On a state level, individual duck boats are also required to be registered and titled for roadway use with PENNDoT and must meet annual inspections required of medium and heavy trucks and buses.
Ride the Ducks reported to the National Transportation Safety Board 11 accidents in 2006, 12 in 2007 and nine in 2008 all of them minor. None of the incidents happened on the water, and no injuries appear to have resulted. Figures for 2009 were not available.
PennDOT spokeswoman Danielle Klinger said inspection records are kept by individual inspection stations and those records for Ride the Ducks were not immediately available Wednesday.
Once the duck boats launch from a ramp onto the water, they are regulated by the U.S. Coast Guard which, according to Ride the Duck's website, regularly inspects, tests and certifies the duck boats.
The company operates about 90 vessels in several cities, including Atlanta, Baltimore, Memphis, Tenn., and Branson, Mo.
The company is currently owned by the Herschend Family Entertainment company, which is located near Atlanta and operates Camden's Adventure Aquarium, the Dollywood theme park, as well as many water and adventure parks.
Contact staff writer Nathan Gorenstein at 215-854-2797 or email@example.com.