A gut is narrow coastal body of water, a channel or strait, usually one that is subject to strong tidal currents flowing back and forth. Many guts are straits but some are at a river mouths where tidal currents are strong. The comparatively large quantities of water that flow quite quickly through a gut can cause heavy erosion that results in a channel deeper than the rest of the surrounding seabed, and the currents may present a hazard to ships and boats at times.