The foc’sle, or forecastle, is the area of the Main Dock forward of Turret I and contains equipment used for anchoring, handling lines, ventilation, and defense. Two anchor windlasses raise and lower the anchor chains, with motors for the gear-driven windlasses several decks below, and each iron link in the chains weighs 80 pounds as the chains are stored in a chain locker several decks below. Capstans of several sizes turn to handle lines and have gear boxes driven by electric motors. Bucket vents at the breakwater supply and exhaust air for interior decks in the forward part of the Ship, while numerous vents throughout the Ship provide air exchange, and a gooseneck vent lets air move in and out of water tanks to equalize pressure. Anchor windlass controls include a wheel marked hoist and lower for raising and lowering the chains and a brake wheel marked brake with arrows showing how to activate it. The breakwater stretches across the foc’sle like a low steel shield and deflected water away from Turret I and the rest of the Main Deck. The ship also used paravanes, torpedo-shaped devices that defended against moored mines by cutting their cables with serrated jaws so the freed mines floated to the surface and could then be detonated by gunfire. Because buoyant mines would float unless tethered to the sea floor, a cable connected each mine to a heavy weight on the bottom, and the cable length determined the mine’s depth. When entering an area suspected of containing moored mines, the Ship rigged paravanes with a complex system of supports and cables, set them out from the sides of the Ship, and kept them at a constant depth at least five feet below the keel, the very bottom of the Ship. Lines attached to the bow towed the paravane, and when the towing cable encountered a mine cable, the mine cable slid down along the towing cable and away from the Ship until the serrated teeth caught and cut it.