NTSB published its report on the March 19, 2021 incident, when the towing vessel Kevin Michael struck the bull nose of the upstream main lock chamber guide wall at the Melvin Price Locks and Dam in Alton, Illinois, resulting in the tow breaking apart and damaging the dam gates.
The incident
The Kevin Michael departed Hennepin, Illinois, on March 17, 2021, and headed down river on the Illinois and Mississippi Rivers for St. Louis, Missouri. During the casualty transit, the Kevin Michael had a crew of nine. The captain was in charge of the vessel and shared helm duties with the pilot.3 The captain and pilot stood 6-hours-on/6-hours-off watch cycles, with the pilot taking the 1100–1700 and 2300–0500 watches, and the captain taking the opposite shifts.
The 15 hopper barges (nine loaded with corn or grain and six empty) were arranged in three strings across (widthwise side by side) and five deep (lengthwise one after the other). All six empty barges were at the front of the tow. The barges were 195 or 200 feet long and 35 feet wide. The entire tow (vessel and barges) was 1,175 feet long and 105 feet wide.
The transit was uneventful, and, on the morning of March 19, the tow neared the Melvin Price Locks and Dam. At the time of the casualty, the river gage at the dam measured 22.8 feet and was rising, and all nine dam gates were raised above the water, between 5 and 8 feet. The Waterways Action Plan (WAP) for the Upper Mississippi River defined this river level as the high-water “watch” phase, which began when the gage measured 21 feet (see section 1.3.3 Waterways Action Plan). During this phase of rising water, the WAP encouraged towboat operators to 1) be experienced in high-water operation, and 2) use caution in all passing and meeting situations.
At 1100, 38 minutes before the casualty, the Kevin Michael pilot relieved the captain of the watch in the wheelhouse. At 1123, the Kevin Michael sailed through the Clark Bridge. The pilot recalled being at a quarter to a third ahead on the engines; that the wind gauge on board the Kevin Michael was reading “15 to 20, and sometimes… 30 [mph] or more;” the wind was on his port side; and the current was “swift.” Because of the wind and current, the pilot desired to make a wide approach to the forebay to align the tow for entry into the main lock chamber, staying closer to the left descending bank. He also desired to keep the tow into the wind so he could land the head of the tow about halfway down the lock chamber guide wall at a point 800–1,000 feet from the bull nose (the rounded end of the guide wall).
Up until 1129, the electronic chart system (ECS) lateral slide indicator for the vessel, which showed the speed of sideways movement perpendicular to the course over ground, was near zero. At 1130, the tow was about 300 feet to the right of the sailing line, aligned with the auxiliary lock chamber upstream guide wall (the sailing line on inland navigational charts is the preferred or recommended route within the reaches of a navigable channel). The upstream guide walls were separated by 400 feet.
Between 1130 and the time of the contact 8 minutes later, the lateral slide indicator showed the bow and stern moving to starboard (toward the center of the river) with a few short movements to port. The pilot told investigators that when the head of the tow was about 1,000 feet from the bull nose of the main lock chamber guide wall (between 1135 and 1136 based on ECS data), he became concerned with the approach into the lock chamber because the outdraft “really got strong,” and the wind was pushing the tow sideways across the river more than he anticipated. The pilot radioed his concern to the two crewmembers at the head of the tow who were providing him with distances to the guide wall.
At 1138, the empty outboard barge in the second row on the starboard side string contacted the guide wall bull nose, causing the tow to break apart. At the time of the contact, the tow’s speed over ground was 4 mph, its heading was 116°, and its course over ground was 132°. In the minute before the contact, the lateral slide indicator showed speeds as high as 6.1 feet per second (4.1 mph) at the bow and 2.1 feet per second (1.4 mph) at the stern.
Eight barges drifted into the forebay area north of gates 1 and 2, with one barge entering the open main lock chamber. Seven barges drifted into gates 3–9. Following the barge breakaway, the lock was closed to traffic. Nearby towing vessels rounded up the barges. The lock reopened the next day, March 20, at 1950. The lock closure delayed seven southbound and three northbound tows.
Analysis
After transiting through the Clark Bridge and approaching the upstream lock of the Melvin Price Locks and Dam, the Kevin Michael’s pilot knew that, under the dam flow conditions and prevailing winds, a successful landing on the lock’s guide wall depended on placing the tow nearer the left descending bank of the river as he approached the forebay, and he tried to move his tow in that direction. Despite lining up in a position he felt would provide for a successful approach to the forebay, the tow slowly slid toward the center of the river and contacted the guide wall. He was unsuccessful because the forces of the dam-induced outdraft and wind acting on the tow overcame the developed forces of the Kevin Michael’s engines and rudders from his orders, setting the tow to starboard and toward the center of the river before contacting the guide wall’s bull nose.
Though the outdraft and wind conditions increased the difficulty for landing the tow on the main guide wall, the pilot anticipated the conditions and expected to enter the lock’s forebay successfully. Based on the WAP guidance, the Coast Guard and other waterway stakeholders judged the water level and flow conditions to be within the capability of pilots experienced with high-water operations on the Mississippi River. The pilot used his knowledge, experience, and judgment to assess conditions and then make decisions regarding his vessel. As the pilot of the Kevin Michael passed through the Clark Bridge and prepared to enter the lock 1.3 miles ahead, he was aware of the increased outdraft in the approach to the lock because he was familiar with transiting the Melvin Price Locks and Dam and knew the dam gates were fully open (above the surface). He was also aware of the gusting wind, which he was monitoring by observing the vessel’s anemometer.
There were no restrictions for operators transiting the locks on the date of the casualty. The Coast Guard was monitoring the water levels and the dangers caused by the currents associated with high water. The pilot met the WAP recommendation that towing vessel operators transiting during a high-water watch phase should have high-water experience.
Based on a safety improvement effort in response to several casualties where vessels contacted the Melvin Price Locks and Dam guide wall, in 2018 the Corps of Engineers, at the request of other towing vessel operators, moved the sailing line—the preferred or recommended route within the reaches of a navigable channel. The sailing line was moved toward the left descending bank of the river to compensate for the outdraft that set tows sideways to their intended course, toward the center of the river, before the approach to the guide wall. Though the pilot was unaware that the Corps of Engineers had addressed the risk from the outdraft by moving the sailing line, he had made many successful transits through the Melvin Price Locks and Dam since 2018. Although his course, which was based on experience and knowledge, was closer to the bank than the original sailing line, it was not as close to the bank as the revised sailing line, which left the Kevin Michael’s pilot with less room to compensate for the strong outdraft and high winds as the tow approached the locks.
Conclusions
#1 Probable Cause
The National Transportation Safety Board determines that the probable cause of the contact of the Kevin Michael tow with the Melvin Price Locks and Dam guide wall was the Kevin Michael pilot not effectively compensating for the strong outdraft and wind above the dam while navigating toward the lock during a period of high-flow conditions.
#2 Lesson Learned: Use of Charted Sailing Lines
Generally, a sailing line is assigned to a known safe route used by commercial vessels. A sailing line is developed under considerations of channel depth, current
patterns, and any other known obstructions to navigation. In some areas, a sailing line is positioned to address a specific navigational hazard, such as the outdraft near the Melvin Price Locks and Dam. A charted sailing line provides for a safe and successful transit when used as a guide along with the mariner’s own experience and assessment of the existing circumstances.
EXPLORE MORE AT NTSB’S REPORT ON THE ACCIDENT
