The West Tisbury and Oak Bluffs fire departments held a drill on Old County Road in West Tisbury on Monday night. The drill was designed to practice what Lt. Brynn Schaffner calls the West Tisbury Fire Department’s “bread and butter” — water shuttling. “During a large fire, our two engines will be used at the fire scene doing fire attack,” Lt. Schaffner wrote in an email. “So we need another engine to come up to West Tisbury to fill up our tankers from a static water source. Per our mutual aid agreement, Tisbury would be one of the first towns called in to help staff our fire ground personnel. That means they go straight to the scene. We would then call in Oak Bluffs to send up an engine to fill our trucks. And then, [depending on the size of the fire], we would also ask Chilmark and Aquinnah to each send a tanker as well.