Lured by "fresh fish served quickly" and on the "cheap", seafood-seekers catch what they're craving at this "airy", industrial "sea shack" in Georgetown, ordering "fast-food" style, plonking their trays on communal "indoor picnic" tables and digging into lobster rolls that are "worth it, even if they leave you longing for seconds"; they also offer full lobster-pot dinners to go, and there are...