BRANSON, Missouri - The National Transportation Safety Board released its preliminary report on the investigation into the fatal duck boat sinking on Table Rock Lake near Branson July 19. Seventeen people were killed when Stretch Duck 7 went down in about 15 feet of water and came to rest on the lake floor at a depth of 70 feet, according to NTSB.

The preliminary report is the first report NTSB will release on the crash and mostly reviews the evidence gathered so far. The report notes local area forecasts included thunderstorm warnings, and data from a nearby vessel indicates winds of over 70 mph.

Investigators have recovered video files from a data card for the Duck's video recording system, the report states. They are examining other electronic devices like cell phones and a camera recovered from the boat. 

They're also reviewing weather data and 33 interviews of witnesses, vessel operators, inspectors and company officials. 

Finally, the report notes that Stretch Duck 7 was an amphibious vehicle that took passengers on tourist excursions on land as well as in the waters of Table Rock Lake.

"These amphibious vehicles are either military-modified, known as DUKW boats, or purpose-built, commonly referred to as DUCK boats. Both types are operated by different companies around the United States and the world," the report states.

The NTSB has investigated other incidents with similar vessels including the 1999 sinking of the Miss Majestic DUKW boat near Hot Springs. The board said investigators noted vehicle maintenance, Coast Guard inspections, reserve buoyancy and survivability as safety issues in that sinking.