The 159 passengers aboard the 113-foot Victoria Clipper III catamaran got off safely at Shilshole Marina, Clipper Vacations spokeswoman Janis Smith said. The company sent buses to take the passengers back to the Seattle waterfront pier where they began their trip.
"Everything was fine," passenger Diane Hanson told KING-TV. "There was no drama."
The ship was just off Edmonds, north of Seattle, when a fire was reported in some insulation surrounding one of the turbine engines, Smith said. The crew sealed that compartment and deployed a chemical fire suppression system, then diverted to the nearby marina, she said.
Seattle Fire Department spokesman Kyle Moore confirmed that the chemical fire suppression system knocked down the fire.
The cause of the fire was under investigation, Moore said.
The Victoria Clipper crew notified the Coast Guard and Seattle Fire, then headed for a nearby place to dock.
"Our first concern was the safety of the vessel and the passengers," Smith said.
The Coast Guard dispatched a 45-foot response boat, Petty Officer Jeremy Gaul said.
The Clipper Vacations website says the San Juan Islands day trip features whale watching and a stop at the town of Friday Harbor.