NTSB finds probable cause in Branson duck boat accident
The National Transportation Safety Board said during a public board meeting Tuesday, the continued operation of amphibious passenger vessel Stretch Duck 7 during severe weather led to the fatal, July 19, 2018, sinking of the vessel on Table Rock Lake, Missouri. Read the full press release below:
The 33-foot-long, modified, World War II-era DUKW amphibious passenger vessel, operated by Ripley Entertainment Inc., dba Ride The Ducks of Branson, sank during a derecho on Table Rock Lake near Branson, Missouri. The vessel had 29 passengers and two crewmembers aboard for a tour. One crewmember and 16 passengers died in the accident.
Ride the Ducks of Branson continued to operate waterborne tours after a severe thunderstorm warning had been issued. This exposed the vessel to a derecho, which resulted in waves flooding through a non-weathertight air intake hatch on the bow, which caused the vessel to sink, the NTSB determined.
Contributing to the duck boat’s sinking was the U.S. Coast Guard’s failure to require sufficient reserve buoyancy in amphibious vessels. NTSB investigators found that the accident vessel was originally constructed with a low freeboard, an open hull, and no subdivision or flotation, resulting in a design without adequate reserve buoyancy. Additionally, the NTSB cited previous inaction to address emergency egress on amphibious passenger vessels with fixed canopies which impeded passenger escape from the Stretch Duck 7.
Tuesday’s board meeting was held virtually due to the COVID-19 restrictions on public gatherings. The proceedings were also webcast, a standard procedure for all board meetings.
“Had Ride The Ducks employees taken more appropriate actions and made better decisions, it is likely the duck boat would not have sunk, because they would not have continued operations based on the weather forecast and prevailing conditions,” said NTSB Chairman Robert Sumwalt.
In their investigation, NTSB investigators documented that the National Weather Service had issued a severe thunderstorm watch for the area, several hours before the sinking. That watch was followed by a severe thunderstorm warning 23 minutes before Stretch Duck 7 departed the shoreside boarding facility about 6 miles from the lake where the tours began and ended. Investigators noted three other company vessels also departed after the severe thunderstorm warning was issued.
The NTSB said the fixed canopy of the Stretch Duck 7 contributed to the severity of the accident as the canopy’s design impeded passenger egress as the vessel took on water and sank. When the vessel sank, the closed starboard-side curtain aboard the vessel impeded the passengers’ escape and likely resulted in additional fatalities, the NTSB concluded.
The NTSB issued six safety recommendations with three recommendations issued to the Ripley Entertainment Inc. dba Ride The Ducks and three recommendations to the US Coast Guard. These recommendations address safety issues including company oversight, engine compartment ventilation closures, reserve buoyancy, survivability, weather training for mariners, and Coast Guard guidance.
The NTSB issued two safety recommendations. Nov. 13, 2019, calling for sufficient reserve buoyancy and improved emergency egress on DUKW amphibious passenger vessels.
An abstract of the NTSB’s final report, which includes the findings, probable cause, and all safety recommendations, is available at https://go.usa.gov/xvEzG.
The final report for the investigation is expected to be published in the next few weeks.
1. The Stretch Duck 7’s propulsion, steering, and bilge systems operated normally and
thus were not factors in this accident.
2. Neither alcohol nor other impairing drugs were factors in this accident.
3. On the day of the accident, the National Weather Service accurately forecasted and
issued timely notifications of a severe thunderstorm that would impact the accident
location.
4. Ride the Ducks did not effectively use all available weather information to monitor
the approaching severe weather and assess the risk it posed to its waterborne
operations.
5. Ride the Ducks should have suspended waterborne operations for the Stretch Duck 7
and the other last tours of the day in anticipation of imminent severe weather.
6. Ride the Ducks should have had specific guidance for the operations team to
determine when to suspend waterborne operations due to approaching severe weather
(go/no-go policy).
7. It is likely that the captain believed he could safely complete the waterborne portion
of the tour before the thunderstorm arrived.
8. The captain’s decision to head toward the exit ramp when encountering the severe
weather was appropriate.
9. Initial water ingress to the Stretch Duck 7 was likely from waves rolling over the air
intake hatch’s spring-loaded damper and intermittently opening it, thereby allowing
water into the engine compartment.
10. The rapid sinking of the Stretch Duck 7 resulted from uncontrolled progressive
flooding due to a lack of subdivision.
11. Had the Coast Guard implemented Safety Recommendation M-02-1 to require
sufficient reserve buoyancy through passive means, the Stretch Duck 7 likely would
not have sunk.
12. The Stretch Duck 54 was able to exit the lake while exposed to the same conditions
as the Stretch Duck 7 due to the increased freeboard, greater reserve buoyancy, and a
securable bow hatch that prevented the ingress of water.
13. When the vessel sank, the closed starboard-side curtain aboard the Stretch Duck 7
impeded egress and likely resulted in additional fatalities.
14. Donning lifejackets on the Stretch Duck 7 while fitted with an overhead canopy
would have created an impediment to escape, would have increased the risk of
persons being entrapped, and could have resulted in additional fatalities.
15. The actions of the crew and passengers aboard the Showboat Branson Belle prevented
more fatalities.
16. The response by emergency services was timely and effective.
17. Improved training is needed for small passenger vessel operators on rivers routes to
recognize and better understand weather conditions.
18. Navigation and Vessel Inspection Circular (NVIC) 1-01 did not effectively address
the NTSB’s 2002 recommendation (M-02-2) to require the removal of, or the Coast
Guard’s approval of, fixed canopies and, consequently, likely increased the number
of fatalities.
19. Navigation and Vessel Inspection Circular (NVIC) 1-01 does not account for
circumstances found in the Stretch Duck 7 accident, including operations during
approaching severe weather and emergency egress during rapid sinking, and should
be updated to provide guidance accordingly.