Editing Old Sow whirlpool (section)

==Origin==
[[File:Quoddy_Hellgate.png|thumb|An 1830 map showed the "Quoddy Hell-Gate" of "dangerous whirlpools" off the southern tip of Deer Island.]]
The whirlpool is caused by local [[bathymetry]] and a {{Convert|20|ft|m|adj=on}} tidal range<ref>{{Cite book|last=Management|first=United States Bureau of Land|url=https://books.google.com/books?id=UcHdmolc0KUC&dq=tidal+range+eastport+maine&pg=PA180|title=Proposed 1977 Outer Continental Shelf Oil and Gas Lease Sale Offshore the North-Atlantic States|date=1976|publisher=Department of the Interior, Bureau of Land Management, New York OCS Office|language=en}}</ref> where waters exchange between [[Passamaquoddy Bay]] and the [[Bay of Fundy]], combined with the [[topography]] of the location's sea floor at the confluence of the numerous local currents through channels and over small sea mounts.<ref name=":1">{{Cite book|last1=Burnie|first1=David|url=https://books.google.com/books?id=D36k9fRBxp8C&dq=old+sow+whirlpool&pg=PA80|title=Ocean: The World's Last Wilderness Revealed|last2=Dipper|first2=Frances|date=2008-07-21|publisher=Penguin|isbn=978-0-7566-5706-2|pages=80|language=en}}</ref>

The whirlpools form in an area with a diameter of approximately {{convert|250|ft}}, as determined by the president of the Old Sow Whirlpool Survivors' Association in 1997 by way of an aerial photograph.<ref>{{Cite web | url=http://www.oldsowwhirlpool.com/vortex.htm |title = Into the Vortex -- Old Sow Whirlpool}}</ref> The photograph was calibrated using the Deer Island Point Light beacon tower of known width that was included in the photograph.

Old Sow is one of five significant whirlpools worldwide ([[Gulf of Corryvreckan|Corryvreckan]], [[Scotland]]; [[Saltstraumen]], [[Norway]]; [[Moskstraumen]], Norway; and the [[Naruto whirlpools]], [[Japan]] are the others).<ref name=":1" /> Although the tidal currents within Western Passage surrounding Old Sow compare with faster whirlpools elsewhere, the speed of Old Sow's vortex is considerably slower than the Moskstraumen, the world's most powerful whirlpool.
{{Wikisource|A Dangerous Whirlpool}}

Tremendous water turbulence occurs locally in the greater Old Sow area, but it does not usually constitute a navigation hazard for motorized vessels with experienced operators at the helm; however, small craft—especially vessels with keels (sailboats) and human-powered vessels—are warned to avoid these waters when the tide is running.<ref>{{Cite web|last=Godfrey|first=Robert|date=August 2001|title=Close Encounters With the Old Sow|url=https://www.smithsonianmag.com/travel/close-encounters-with-the-old-sow-48091759/|access-date=2021-04-18|website=Smithsonian Magazine|language=en}}</ref>

Besides Old Sow and its numerous "piglets" (small and medium whirlpools surrounding Old Sow), other area phenomena include standing waves, upwellings (that on rare occasion may even spout several feet into the air), and {{convert|10-17|ft}} deep or more, circular and trench-shaped depressions in the water.

The failed Passamaquoddy Tidal Power Project/"Quoddy Dam" Project saw a series of tidal dikes constructed during the 1930s to connect [[Moose Island, Maine|Moose Island]] ([[Eastport, Maine]]) to Carlow Island (in Eastport), Carlow Island to [[Passamaquoddy Pleasant Point Reservation|Pleasant Point]] and to connect Treat Island (in Eastport) to Dudley Island (in [[Lubec, Maine]]). The changes in local water flow from the dikes reportedly reduced predictability of the "funnel" effect of Old Sow.<ref name=":0">{{Cite web|url=https://newengland.com/yankee-magazine/travel/maine/eastport-maine-tidal-project/|title=Eastport, Maine Tidal Project|website=newengland.com|language=en-US|access-date=2018-08-07|date=2015-08-25}}</ref>