On the afternoon of March 31, 2016, the passenger vessel Adventure Hornblower was attempting to dock at the Navy Pier in downtown San Diego, California, following a whale-watching excursion. As the vessel made its approach to the pier, its bow unexpectedly swung to starboard and allided with the pier's passenger embarkation dock. The Adventure Hornblower then accelerated forward until it struck the seawall at the foot of the pier. Eight passengers sustained minor injuries in the accident. The allision caused nearly $1.06 million in damage to the vessel, pier, and seawall.

​​​The probable cause of the allision of the Adventure Hornblower​ with the Navy Pier and the downtown San Diego seawall was a failure of the port transmission to disengage from the forward propulsion position due to the operating company’s lack of adherence to the transmission manufacturer’s recommended periodic maintenance schedule and the lack of routine maintenance and upkeep of the propulsion system’s equipment. Contributing to the accident was the lack of instrumentation to provide positive indication of thrust direction or an alarm to indicate the propulsion control system was not responding properly to the captain’s commands.

​​Adherence to Manufacturer’s Recommended Maintenance Procedures and Intervals

This accident illustrates the potential safety hazards of failing to follow the equipment manufacturer’s recommended maintenance procedures and schedules. Without necessary maintenance, equipment cannot be relied on to perform as designed. Mariners should review manufacturer manuals and guidance on a regular basis to ensure conformance with recommended maintenance plans.

Access to Vessel Controls and Distraction

Vessel controls that are located outside the bridge/wheelhouse and are accessible to non-crewmembers present the opportunity for tampering and may lead to the distraction of the operator. Owners and operators should designate a perimeter around these stations and ensure the area is secured when in operation.

Remote Propulsion Control Systems

Current technology allows vessels to be constructed and fitted with automated instrumentation and alarms that alert the operator in the event of critical failure; however, they are not required by regulation. The negative consequences of an undetected loss of propulsion control are elevated for passenger vessels because they carry more people on board, often transit in confined waterways, and dock frequently. Owners and operators are encouraged to install instrumentation that provides a positive indication of propulsion thrust direction and/or a deviation alarm at bridge/wheelhouse and remote propulsion control stations. Such indications/alarms increase the likelihood of early detection of improper propulsion response, thereby allowing the operator time to take effective corrective action.