It’s been one hot summer so far (albeit a bit rainy) and what better way to cool off than with a dunk into Boston Harbor? Only 10 lucky folks will be picked to jump into the water — they’ll take the plunge off of historic tall ship Roseway which will be docked a Pier 6 for the 4th Annual Walk The Plank, a fundraiser for World Ocean School programs. Even if you don’t plan on getting wet, you can come to cheer on the plank walkers and enjoy live music from Mama’s Black Sheep and tasty eats courtesy of the talented culinary team at the Charlestown seafood spot. Bring a wad of bills for the cash bar and make sure to swing past the silent auction at the event, which runs from 4:30 to 8:30pm. It’s free to stop by, but get all the details here.