The Tacoma stalled July 29 near Bainbridge Island. Another ferry diverted to help, pulling it away from shore until two tug boats could bring it in to the dock.
In an online newsletter, the ferry system said Friday that an initial update on the vessel's repair plan from Siemens Marine Solutions indicates how the problem began. The report says a fuse blew in the vessel's propulsion control system without any indication to the operating engineers - and that triggered a chain of events that led to the power failure.
The ferry system says it continues to review the cause of the incident.