Captain Error Leads to Tugboat Striking Bridge Fender, NTSB Report Finds

The National Transportation Safety Board said Tuesday that the captain of an articulated tug and barge (ATB) failed to line up his vessel correctly while approaching the Hylebos Bridge in Tacoma, Washington, last year, causing an assisting tugboat to strike the bridge’s already deteriorated fender system.

The incident occurred on October 12, 2023, when the tugboat Olympic Scout was assisting the ATB Montlake/Sodo as it navigated outbound on the Hylebos Waterway in Tacoma. The Montlake was coupled to the Sodo, a 289-foot-long, 78-foot-wide barge, forming an articulated tug and barge unit.

The NTSB reported that the Montlake/Sodo’s captain requested the Hylebos Bridge operator to open the bridge. While waiting, the ATB had to pause, causing its bow to drift from the channel’s center towards port (the left side). Although the captain attempted to steer starboard to align with the bridge, the drag from the Olympic Scout on the port bow prevented the ATB from moving in that direction.

Damage to Hylebos Bridge fender system following the contact. Source: U.S. Coast Guard

When the Montlake/Sodo began its transit of the waterway, it was 1,276 feet from the bridge. The channel between the Hylebos Bridge fenders measured 150 feet wide. However, the combined width of the Montlake/Sodo (78 feet) and the Olympic Scout (26 feet) was 104 feet, leaving only 23 feet of clearance on each side of the vessels.

Investigators concluded, “Because of the short distance to the bridge and the speed of the ATB, there was insufficient time to correct the lineup before the Olympic Scout struck the fender.” They suggested that “slowing or fully stopping the ATB’s forward motion earlier would have provided the operators more time to correct the lineup and successfully transit through the opening between the bridge’s protective fendering.”

While the Hylebos Bridge itself remained undamaged, the fender system required replacement at a cost of $2.43 million. Notably, precasualty inspections in 2017 and 2022 had already identified significant deterioration of the fender piles due to marine borer damage and fungal decay. A marine surveying and consulting firm stated, “The damage caused by the [Olympic Scout contact] resulted in significantly more damage being sustained as would have been, had the fendering structure been of sufficient structural strength.”

You can find the NTSB report here.