Washington State Ferries will hold a drop-in open house Saturday afternoon to give information and take feedback on upcoming changes to the north-end ferry schedule.

The state announced last month that it will add a larger ferry to the north-end triangle route next fall and at the same time eliminate some runs throughout the day, allowing for more time between sailings. The new boat configuration and sailing schedule, officials say, will allow the ferries to carry the same number of cars throughout the day while more easily keeping to the schedule on a route that has become known for frequently falling behind.

On Saturday, ferry officials will be on hand at the Ober Park Performance Room to discuss the upcoming changes and hear islanders’ thoughts on the schedule rewrite — the first change to the north-end schedule in 10 years.

WSF Director David Moseley said the officials would come with information on current ridership, sailing times and dwelling times — the amount of time ferries spend at the dock between sailings. Officials say that the triangle route is tightly scheduled, meaning boats are often delayed by even minor disruptions such as heavy traffic, fog or emergency medical transports.

“We’re trying to make this as much as possible a data-driven discussion,” Moseley said.

Meanwhile, Vashon’s ferry advocates are trying to call attention to the schedule rewrite, saying it’s bad news for ferry riders.

Greg Beardsley, head of Vashon’s Ferry Advisory Committee and a member of a steering committee WSF formed to provide feedback on the rewrite, has released some draft schedules he received as part of the group.

The two options drafted by WSF show that several trips would be deleted each day on the triangle route and there would be more time scheduled between the remaining sailings. Beardsley has designed detailed spreadsheets comparing the draft schedules with the current one as well as charts showing the number of vehicles per sailing and the excess or deficit vehicle spaces each sailing would run with He has been distributing them via email to ferry riders.

Another concerned ferry rider who commutes from Southworth and is part of the local Ferry Community Partnership has posted fliers with warnings about the changes on the King County Water Taxi, and Beardsley said he expected fliers would be posted on car ferries as well. The fliers encourage riders to attend the open house and email Beardsley for the draft schedules.

“For everyone who has to use the ferries regularly, this schedule change could be very detrimental,” Beardsley said.

Beardsley said he believes a final schedule proposal — not due out until early next year — will look very similar to the drafts unless islanders express their concerns now.

“I hope people tell them this does not work for them, and hopefully that will be enough to get this rolling,” Beardsley said.

Moseley, however, said ferry officials are still early in the schedule drafting process and he hopes islanders won’t jump to conclusions about the draft schedules being distributed.

The agency plans to present a schedule proposal, hold another public meeting and take public comments on it in February of 2014. It will revise the schedule by the springs and implement the new sailing times in September of 2014.

“We have a long way to go before we are in any position to make any schedule recommendation to the community,” Moseley said. “We’ll look at a lot more schedule options.”

The drop-in open house will be from noon to 3 p.m. Saturday at the Ober Park Performance Room at the Vashon Park District offices.