The Seattle Maritime Festival expands a day, to Sunday, May 11, at the working waterfront at Lake Union Park, in addition to the popular annual activities Saturday, May 10, at Pier 66 and Bell Harbor Marina on the downtown waterfront.

Tugboat championship races from Pier 62/63 to Pier 86, the largest tugboat races in the world and a 30-year tradition, are Saturday’s main event. Festivities start with a fireboat display at noon, followed by workboat parade and a tugboat ballet/demonstration at 1 p.m., Coast Guard sea-air rescue demonstration at 1:40 p.m. and tug races at 2:10 and 2:45 p.m.

Tugboats and other workboats and Coast Guard ships will be open to tour throughout the day, and free working-waterfront harbor tours are available at noon, 2 and 4 p.m. (limited to 200 guests per tour).

Industry exhibits fill the plaza at Pier 66, and several local restaurants compete in the Seattle Waterfront Neighborhood Chowder Cook-Off judged by festivalgoers with a $5 tasting fee to benefit maritime community and youth organizations.

Sunday’s new Maritime Festival Family Fun Day at Lake Union Park features tours of historic and working vessels, kids activities, music, Workboat World Invitational Boat Building Competition and Survival Suit Races — in which teams of four compete to be the fastest to don survival suits, jump into Lake Union, swim to a life raft and climb aboard. Seattle Flying Dragon hosts hourly dragon boat races, and free Lake Union/Ship Canal boat excursions are available at 1 and 2:30 p.m. (space limited).

Kids activities include free boat building at the Center for Wooden Boats, storytelling aboard a tugboat, craft activities and bounce houses ($5 for unlimited rides). Food vendors, a beer garden, industry displays, and Center for Wooden Boats displays and activities continue throughout the event.

Lake Union Park, 12 acres of green space and waterfront formerly owned by the Navy, is Seattle’s newest major park, completed in 2010 and home to the Museum of History & Industry (MOHAI) and the Center for Wooden Boats.

The South Lake Union Street Car runs every 15 minutes between downtown Seattle and the park; public parking is available along Westlake Avenue North on the north side of Lake Union Park.

Madeline McKenzie: mmckenzie@seattletimes.com