On 3 May 2017, the USCG response boat ‘CG 29113’ allided with the Highway 11 Bridge while responding to a non-distress search and rescue case involving an adrift sailboat in Lake Pontchartrain, Louisiana. The accident caused a minor injury to one USCG crew member and damage estimated at $337,000 to the CG 29113. The sailboat, valued at $20,000, eventually sank. The NTSB issued an investigation report on the incident.
The incident
At 1515, on the day of the accident, USCG Sector New Orleans received a call from the St. Tammany Parish Sheriff’s Office reporting that a 32-foot-long dilapidated sailboat with no one onboard was adrift near the Highway 11 Bridge in Lake Pontchartrain. The day before, the owner had inadvertently grounded the sailboat on a nearby sandbar and abandoned the vessel after reportedly securing it with two anchors. The sailboat had subsequently become dislodged and, on the day of the accident, authorities could not reach the owner to retrieve the sailboat.
As such, Sector New Orleans directed USCG New Orleans to launch a vessel to assess the situation and, if safe to do so, tow the vessel to keep it from striking the bridge or in general presenting a hazard to navigation. Accordingly, Station New Orleans trailered its 29-foot-long response boat-small (RB-S II) CG 29113 to a nearby boat ramp.
The four crewmembers decided to tow the sailboat from the scene. Because of the sailboat’s position against the bridge and because the jib sail covered the forward bitt, USCG crewmembers were unable to tow the sailboat in a standard configuration from its bow. Instead, they attached a bridle to two bitts on the sailboat stern to tow the vessel in a stern-to-stern configuration.
About this time, the weather began to deteriorate due to strong thunderstorms in the area. During the tow, the winds were gusting up to 39 mph, and the waves reached 4–6 feet. The crew observed waves washing over the sailboat’s stern, which by design was already low to the waterline, and the vessel started taking on water. The crew then tried to reconfigure the tow, but in the course of doing so, the sailboat began to sink in the high waves.
In addition, its mast broke and struck the CG 29113 taffrail. While dodging the falling mast, the crew tossed the detached bridle lines into the water and also tried to manuever the CG 29113 away from the sailboat to avoid collision. About that same time, the CG 29113 lost engine power and propulsion.
After the crewmembers tried unsuccessfully to restart the engines, they saw that the bridle lines were fouled in the propellers and they tried to clear them. Meanwhile, the waves and the strong current caused the CG 29113 to drift into the Highway 11 Bridge, alliding with the bridge’s fendering system and concrete pilings.
The initial impact was on the CG 29113’s starboard side. The vessel then drifted under the bridge, and its port side struck the pilings. Eventually, the crewmembers were able to restart the port engine and maneuvered the CG 29113 to a safe area northeast of the bridge. Once away from the bridge, the crew managed to also restart the starboard engine and proceeded to the nearest ramp. The sailboat ultimately sank.
Probable cause
NTSB determines that the probable cause of the accident was the challenging circumstances during a stern-to-stern tow in deteriorating weather conditions, which fouled the CG 29113’s propellers and caused a loss of propulsion. Contributing to the accident was the dilapidated state of the sailboat, which complicated the attempt to tow the vessel, which subsequently sank.
The Coast Guard’s decision to attempt a tow was reasonable, as the Vanguard sailboat had drifted up against a highway bridge, presented a general hazard to navigation, and may potentially have been leaking fuel. The sailboat’s position against the bridge did not allow for a standard towing configuration, and the onset of thunderstorms produced increasing winds and waves that further complicated the tow.
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