NTSB investigation: Houston Ship Channel collision attributed to speed

The incident

On May 10, 2019, the 754-foot-long, 122-foot-wide LNG carrier Genesis River had been outbound on the Houston Ship Channel when it met the inbound 740-foot-long, 120-foot-wide liquefied gas carrier BW Oak in the intersection of the Houston Ship Channel and the Bayport Ship Channel, known as the Bayport Flare.

After the Genesis River and the BW Oak passed each other port side to port side, the Genesis River approached the southern terminus of the flare and a 16-degree port turn in the channel. As the Genesis River exited the flare and entered the turn, it crossed over to the opposite side of the Houston Ship Channel and subsequently struck the starboard barge in the Voyager’s two-barge tow.

The Genesis River’s bow penetrated through the barge’s double hull and breached its center cargo tanks. The force of the collision capsized the port barge in the tow, and the Voyager heeled considerably before its face wires parted and the vessel righted itself. Over 11,000 barrels of reformate, a gasoline blending stock, spilled into the waterway from the starboard barge’s breached cargo tanks.

As a result, the Houston Ship Channel was closed to navigation for two days during response operations and did not fully open for navigation until May 15. The total cost of damages to the Genesis River and the barges was estimated at $3.2 million. The cost of reformate containment and cleanup operations totaled $12.3 million. There were no injuries reported.

Probable causes

​NTSB determines that the probable cause of the collision between the Genesis River and the Voyager tow was the Genesis River pilot’s decision to transit at sea speed, out of maneuvering mode, which:

• increased the hydrodynamic effects of the Bayport Flare’s channel banks,
• reduced his ability to maintain control of the vessel after meeting another deep-draft vessel, and
• resulted in the Genesis River sheering across the channel toward the tow.

Operating at sea speed reduces the ability to maneuver out of a dangerous situation. This is especially true in the Houston Ship Channel, a challenging waterway with a long history of accidents,

…said NTSB Chairman Robert L. Sumwalt.

Key findings

1. Pilot and crew credentialing and experience, use of alcohol or other tested-for drugs, fatigue, and environmental conditions were not factors in the accident.
2. Mechanical and electrical systems on the Genesis River and Voyager operated as designed, and their functionality was not a factor in the accident.
3. Although the Genesis River master’s decision to place the vessel’s automated radar plotting aid (ARPA) in standby and turn off the ECDIS deprived the bridge team of critical tools with which to monitor the pilots’ actions and ensure that the vessel transited safely, the status of this equipment was not a factor in the accident.
4. The Genesis River helmsman properly executed the rudder orders of the pilot and his performance was not a factor in the accident.
5. Although the helmsman in training properly executed the orders of the pilot, placing him at the helm without informing the pilot was contrary to good bridge resource management practice.
6. Maintaining stern trim while underway would have improved the handling characteristics of the Genesis River.
7. The combined effect of the speed of the Genesis River and the passing of another large vessel in the asymmetrically shaped channel at the southern terminus of the Bayport Flare resulted in an uncontrollable sheer to port by Genesis River, initiating a chain of events that led to the collision.
8. The BW Oak pilot’s maneuvering of his vessel to prepare for the meeting with the Genesis River was routine and did not impede the Genesis River’s ability to pass.
9. Wide-beam, deep-draft vessels meeting in the Houston Ship Channel in the vicinity of the northern and southern terminuses of the Bayport Flare have a higher risk of loss of control due to complex and varying hydrodynamic forces.
10. Once the Voyager and its tow began the turn to port, the collision was unavoidable.
11. An increase in engine rpm to arrest the Genesis River’s initial sheer, even if promptly executed after it was ordered by the pilot, would not have prevented the collision.
12. The pilot transiting the wide-beam, deep-draft Genesis River at sea speed through the shallow and narrow lower Houston Ship Channel left little margin for error and introduced unnecessary risk.
13. The Genesis River pilot’s decision not to use emergency full astern or the anchors to avoid the collision was reasonable.
14. The actions of the Voyager relief captain to attempt to avoid the collision by crossing the channel were reasonable, given the information available to him at the time he had to make the decision to maneuver.
15. The Genesis River pilot’s early and frequent communications with the Voyager mitigated the impacts of the accident and likely prevented loss of the towing vessel and injuries to its crew.
16. Coast Guard Vessel Traffic Service Houston–Galveston’s response to the collision was timely and appropriate.
17. The Bayport Flare, as well as other intersections within the Houston–Galveston Vessel Traffic Service area, would benefit from regular risk assessments and the consideration of additional vessel routing measures.

Recommendations

As a result of its investigation of this accident, the National Transportation Safety Board makes the following four new safety recommendations:

-To K-Line Energy Ship Management:

• Review your safety management system and develop formalized procedures for watch team reliefs to ensure embarked pilots are informed of a change in personnel, particularly a change in helmsmen.

-To the Houston Pilots:

• Revise guidance to operators of the Genesis River and similar vessels to require vessels to be sufficiently trimmed by the stern prior to transiting the Houston Ship Channel.
• Advise your members to avoid conducting any passing arrangements between widebeam, deep-draft vessels in the northern and southern terminuses of the Bayport Flare.
• Advise your members to avoid transiting wide-beam, deep-draft vessels at sea speed in the lower Houston Ship Channel.

The NTSB also reiterated two earlier recommendations made to the USCG. Those 2016 recommendations urged the Coast Guard to identify areas of increased vessel conflicts or accidents that could benefit from the use of special routing measures.

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