Hours vary by weekend, but a free ferry generally leaves from the Battery Maritime Building (South Street at Whitehall Street) on the hour and returns on the half-hour, starting from 10 a.m., Fridays through Sundays (check govisland.com for a specific schedule). Another ferry leaves Fulton Ferry Landing in Brooklyn on designated weekends. There’s a separate line for bike-bringers that leads to the ferry’s car deck. Except for Water Taxi Beach (which will have a walk-up bar on concert nights), the island is open until 5 p.m. on Fridays and 7 p.m. Saturdays and Sundays.