One of the two ferries on the Coupeville-to-Port Townsend run was knocked out of commission by something that has surprised Washington State Ferries officials.

Lines from crab pots.

State Ferries shuffled boats in the system to return the run to two boats for the weekend, which is expected to be busy because of the Coupeville Arts and Crafts Festival. Historically the run experiences an 11-percent spike in traffic during the second weekend in August, State Ferries reported.

Officials haven’t decided whether to keep the replacement boat on the run beyond the weekend, according to spokesman Ian Sterling.

The trouble started Tuesday when the Salish made a soft grounding because of what’s believed to be a failure of the rudder system. Divers, however, discovered a much more serious problem, Sterling said. Lines from crab pots were tangled in the propulsion shaft, which may have caused damage to the bearing.

Fixing the problem means taking the boat out of the water and dry dock space is scarce in the region.

Sterling said he’s known of fishing nets causing problems for ferries, but never crab pots. It may be related to the sheer number of crab pots in the water, which seems like more than in past years — particularly on the Coupeville side. People even put them right in front of the ferry dock.

“There are an amazing number of crab pots out there,” he said. “It’s not dozens, it’s hundreds and hundreds.”

Because of the number, it’s not possible for ferry captains to steer around the crab pots. Sterling suggests that it’s in the best interest of crabbers and the ferry system for crab pots to be placed well away from ferry routes, though there are no rules in regard to crab pots and ferry runs.

There are only a few ferries in the system that can navigate Keystone Harbor on the Coupeville side of the run. State Ferries moved the Chetzemoka from the Point Defiance-to-Tahlequah run to supplement the Coupeville route for the weekend. The Sealth will move from the north end of Vashon Island down to Point Defiance-to-Tahlequah, State Ferries reported.

“We know shuffling schedules during the summer is a challenge for residents, businesses and tourists, and we want to thank them for their patience,” said Amy Scarton, WSF assistant secretary. “We’ll continue to assess service options beyond Sunday, and we’re exploring all avenues to get the Salish up and running again as soon as possible.”