Thu. Jul. 7 2005 6:42 PM ET The Queen of Oak Bay is examined in order to find out what caused the failure on Thursday. The B.C. ferry smashed into a number of boats and ran aground at a marina while docking at Horseshoe Bay in West Vancouver. Missing cotter pin blamed for B.C. ferry accident CTV.ca News Staff A missing 3 cm cotter pin set off a chain of events that led to the grounding of a ferry at Horseshoe Bay in West Vancouver last week. BC Ferries says a control arm connecting the engine speed control device to the engine fuel rack disconnected when a nut came off the attachment bolt. The nut came off because an inexpensive cotter pin that is normally in place to hold it in place was missing. The disconnection of the bolt allowed the propulsion system to over-speed. Protective devices known as "over-speed trips" then engaged, and led to the shutdown of the propulsion system. The ferry was unable to slow down and crashed into the Sewell Marina, crushing 24 smaller vessels. BC Ferries official Mark Collins called it an anomaly, not a failure of the basic design. The mechanism had been serviced by a private company during the ship's recent $35-million refit at Vancouver Shipyards. The ship received regular engine maintenance along with upgrades of its interior and replacement of piping and cables. BC Ferries is not naming the contractor who performed the maintenance work. Amazingly, no one was injured in last week's accident and the ferry, the Queen of Oak Bay, was only minimally damaged. The vessel was repaired and has now been certified to resume service on its usual Nanaimo-to-Horseshoe Bay route, starting on Friday. BC Ferries says that their other vessels have been checked for the same problem and have been cleared. The ferry operator is now negotiating claims with the 24 owners of the destroyed or damaged boats. Tentative agreements have been reached with three of the owners. BC Ferries president David Hahn, meanwhile, says the 544 passengers aboard the stricken ferry will be compensated with a gif certificate for their ordeal.