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.
The term "gut" is primarily (though not exclusively) applied to channels of the coastal waters of the Atlantic coast of North America. A similar term of related but not identical meaning, "gat", is applied to some narrow waterways of the North Sea and Baltic Sea coasts of Europe.
Some bodies of water named "Gut" are:
Many other channels in Canada are named "Gut". Applied to proper names, "gut" is sometimes used more broadly. For instance South Gut and North Gut at the settlement of South Gut St. Anns, Nova Scotia are just inlets, while Brewery Gut in England and The Gut in Ontario are fast-flowing stretches of river, Jigsaw Rock Gut in Antarctica is a gully, and Gardner's Gut in New Zealand is a cave system. Conversely, some guts are not so named, such as The Rip, a gut in Australia, where the term "gut" is not used.
Another meaning for "gut" in geography is a small creek, and this is seen in proper names in eastern North America from the Mid-Atlantic states (for instance, The Gut in Pennsylvania, Ash Gut in Delaware, and other streams) down into the Caribbean (for instance Guinea Gut, Fish Bay Gut, Cob Gut, Battery Gut and other rivers and streams in the United States Virgin Islands, in many rivers and streams of the Dutch Caribbean, and in Jamaica (Sandy Gut, Bens Gut River, White Gut River)).
A gat (German: Seegatt, Seegat or diminutive Gatje) is a strait that is constantly eroded by currents flowing back and forth, such as tidal currents. It is usually a relatively narrow but deep, up to 30 m (100 ft) passage between land masses (such as an island and a peninsula) or shallow bars in an area of mudflats. A gat is sometimes a shallower passage on lagoon coasts, including those without any tidal range.
According to Whittow a gat is either an inshore channel or strait dividing offshore islands from the mainland e.g. the Frisian Islands, or it is an opening in a line of sea cliffs allowing access to the coast from inland. It is similar, but not identical, to a gut, which is a narrow river channel or strait prior to joining an open ocean or estuary. Leser restricts its use to deep, but relatively narrow inlets in the Wadden Sea that are scoured out by currents, giving the example of the gap between the Frisian islands of Juist and Nordeney.Outline of oceanography
The following outline is provided as an overview of and introduction to Oceanography.Tidal race
Tidal race or tidal rapid is a natural occurrence whereby a fast-moving tide passes through a constriction, resulting in the formation of waves, eddies and hazardous currents. The constriction can be a passage where the sides narrow, for example the Gulf of Corryvreckan and the Saltstraumen maelstrom, or an underwater obstruction (a reef or rising seabed), such as is found at the Portland Race.
In extreme cases, such as Skookumchuck Narrows in British Columbia, through which tides can travel at more than 17 knots, very large whirlpools develop, which can be extremely hazardous to navigation.