![Photo: Kitsap Transit](http://media.assettype.com/bairdmaritime%2Fimport%2Fwp-content%2Fuploads%2FPhoto-Kitsap-Transit1.jpg?w=480&auto=format%2Ccompress&fit=max)
US ferry operator Washington State Ferries (WSF) has begun an investigation into a recent grounding incident involving one of its vessels.
The incident occurred at around 16:40 local time on Saturday, April 15, when the Ro-Pax ferry Walla-Walla lost power and came to rest on a shallow portion of the Rich Passage strait within Puget Sound.
The ferry had departed Bremerton and was en route to Seattle with over 600 people embarked at the time.
Some of the stranded passengers were later brought aboard the fast ferries Waterman and Commander, which were despatched to the area by local operator Kitsap Transit. The passengers were then transported to Bremerton.
Walla-Walla was successfully refloated with assistance from tugs later in the day on Saturday. The tugs then towed the ferry to Bremerton to undergo repairs and to the remaining passengers and the vehicle cargo to be offloaded.
The US Coast Guard had also deployed patrol boats to assist in the rescue and refloating effort.
No injuries or oil spills have been reported while an initial inspection by divers revealed no serious damage to the hull.