increases the visibility of a diver, and reduces the risk of not being noticed by a passing vessel. This will reduce the risks both of being run down and of being lost at the surface. It also provides an additional flotation device in case of fatigue. Signalling the boat If the boat cannot see a diver at the surface, the diver can use several methods to be more visible, and once seen, can indicate to the boat whether they are in difficulty or not. Diving from an anchored boat When using the anchor line to control ascents and descents, a "tag line" (or "lead line") may be used between the anchor line and the stern of the vessel, to allow secure transfer between these points in a current. A floating "drift line" (also "tag line", "current line" or "trail line") may be streamed from the stern or boarding platform to assist divers who drift astern of the vessel, and for something to hold onto while waiting to use the ladder. They can either hold onto the line and be pulled in by the crew, or pull themselves along the line. The far end of the line is usually marked with a brightly coloured buoy to show divers where it is and to help other boats avoid crossing the line. If there is any significant risk of a diver drifting away from the site, the dive boat should either be ready to slip the moorings at short notice, or have a tender in the water. Some skippers will tether the tender behind the dive boat where it can also be used as a drift line. A lazy shot or decompression trapeze may be suspended from the boat near the boarding area, and the drift line may be set up between this and the anchor line to guide decompressing divers ascending on the anchor line to the more convenient facility at the stern for the shallow stops. Live-boating is diving from a boat which is not moored. There are increased risks due to the proximity of the divers to propellers when the engines are running, but there are also safety and convenience advantages to having the boat available to move at immediate notice, particularly in currents, as the boat can follow a group of drift divers, and pick up the divers from where they surface in most cases. Live boating is also