Classification
- Incident Type: Collision
- Severity: High
- Primary Source: NTSB Marine Accident Brief DCA16FM010
Vessel Details
| Field | Value |
|---|---|
| Vessel Name | William E Strait |
| Vessel Type | Tug |
| Flag State | United States [US] |
| IMO Number | |
| Official Number | 270550 |
| Gross Tonnage | 1103 |
| LOA (m) | 56.2 |
| Breadth (m) | 13.7 |
| Year Built | 1955 |
| Crew Size | 9 |
| Other vessel | Margaret Ann, United States towing vessel; 342 GT; 32.2 m LOA; 6 crew; pushing three asphalt tank barges |
Incident Details
| Field | Value |
|---|---|
| Date | 2015-12-14 |
| Location | Lower Mississippi River, mile marker 727.4 |
| Coordinates | |
| Region | United States |
| Fatalities | 0 |
| Injuries | 0 |
| Missing | 0 |
| Direct Damage | William E Strait hull opening and partial sinking; damage to barges MM-66, MM-41B, and MTC 6401 |
| Economic Damage | USD 2 million |
Key facts
- The collision occurred at 1122 central standard time on 14 December 2015 near Lower Mississippi River mile marker 727.4.
- Margaret Ann was downbound with three asphalt tank barges; William E Strait was pushing a flotilla of 30 loaded gravel barges.
- William E Strait sustained a 6-by-5-foot hull opening, flooded rapidly in the engine room, and partially sank on the left descending bank.
- Barges MM-66, MM-41B, and MTC 6401 were damaged; approximately 700 gallons of oil and diesel were released.
- The NTSB determined that the probable cause was the William E Strait pilot's inability to hold the agreed position along the left descending bank.
Narrative
On 14 December 2015 at 1122 central standard time, the downbound towing vessel Margaret Ann was pushing three tank barges loaded with liquid asphalt on the Lower Mississippi River. The United States towing vessel was 32.2 metres long, 342 gross tons, and had six crew members. William E Strait, a 56.2-metre, 1,103-gross-ton United States towing vessel with nine crew members, was pushing a flotilla of 30 loaded gravel barges near mile marker 727.4.
During the watch relief near mile marker 731, the pilots arranged a passing manoeuvre. William E Strait would back slowly off the left descending bank and hold position while Margaret Ann widened its port turn and stayed close to the right bank. Margaret Ann would then continue downriver and William E Strait would follow. As Margaret Ann approached, its pilot observed that William E Strait's stern was moving toward the middle of the channel. The pilots spoke again, and William E Strait's pilot said he intended to use ahead propulsion and swing the stern back toward the bank.
The stern continued to move toward the channel. Margaret Ann's pilot applied hard-starboard rudder and full-ahead throttle to reduce the risk of the lead barge riding up onto William E Strait. The aft port side of barge MM-66 and the port bow of barge MM-41B struck the aft starboard corner of William E Strait. MM-66 suffered a hull penetration and broke free from the tow string; MM-41B sustained bow and forward-deck damage. The impact opened William E Strait's hull by about 6 by 5 feet and rapidly flooded the engine room. The force also pushed its port bow into barge MTC 6401, holing that barge's stern void.
William E Strait was maneuvered back to the left bank with assistance from Paige L Strait. Its crew boarded the aftermost barge before the towing vessel partially sank and came to rest on the river bottom. Margaret Ann, assisted by Lee Leavell, recovered MM-66 and began pumping water from its stern void. The NTSB reported no injuries, estimated property damage at USD 2 million, and recorded approximately 700 gallons of oil and diesel released.
The NTSB determined that the probable cause was the William E Strait pilot's inability to hold his vessel in position along the left descending bank as agreed, which prevented the safe and unimpeded passage of Margaret Ann. Investigators found no known steering, propulsion, or other vital-system problem immediately before the collision. They also noted unresolved watertight-integrity concerns that may have contributed to the rapid downflooding after impact.
Sequence of events
| Date/time | Event |
|---|---|
| 2015-12-14 11:00 CST | The Margaret Ann pilot took over the watch near mile marker 731. |
| 2015-12-14 | The pilots agreed that William E Strait would hold position along the left descending bank while Margaret Ann passed. |
| 2015-12-14 11:22 CST | The Margaret Ann tow collided with William E Strait and its tow. |
| 2015-12-14 | William E Strait's crew transferred to the aftermost barge before the towing vessel partially sank. |
Contributing factors
| Factor | Evidence status | Description |
|---|---|---|
| Failure to hold the agreed position | Confirmed finding | The NTSB identified the William E Strait pilot's inability to hold position along the left descending bank as the probable cause. |
| Current and channel movement | Reported | AIS analysis showed William E Strait shifting toward the channel and no appreciable swing of its stern back toward the bank before the collision. |
| Watertight-integrity concerns | Reported | Investigators noted unresolved watertight-integrity issues that may have contributed to rapid downflooding after the hull was opened. |
Investigation
The National Transportation Safety Board investigated the casualty in Marine Accident Brief DCA16FM010. It determined that William E Strait's pilot failed to hold the agreed position, preventing Margaret Ann's safe passage. The report also recorded the damage, pollution, partial sinking, and the absence of reported injuries.