Quoddy Loop Homepage

Tides

What Causes the Tides?
Area Tidal Wonders
A Note About Tide Times
Quoddy Tidal Power Project

Other Tides Resources
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What Causes the Tides?

Since the Quoddy Loop falls within the Bay of Fundy--which has the greatest tidal range in the world (an occasional range of over 50 feet near the head of the bay!)--the tidal range here is impressive. But, what causes the tides?

The pull of gravity from the Moon and the Sun are the primary cause for tides. The effect is the greatest when the Moon and Sun are in a straight line with the Earth--called "syzygy" (sih' zuh gee)--which occurs during a Full Moon, New Moon, and during a Lunar and a Solar Eclypse.

The configuration of the shore and ocean floor affect tidal range (the vertical difference between high and low stages of the tide). Since the Bay of Fundy has a large mouth, with an ever-narrowing passageway to the head of the bay, the enormous volume of incoming tidal water is forced upward, causing the great tidal differences.

[Check out this comprehensive Moon site.]

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Want to Get Technical?

(Revised 2006 April 1, to account for the Barycenter.)

Oddly, the tide here is high (and also low) twice a day! If the gravity from the Moon--on the Moon's side of the Earth--causes the tide to be high, then how can the tide be high when the moon is on the other side of the Earth?

The Earth and Moon together--due to their gravitational attraction to each other--act as one unit. Think of this body as something like a sledge hammer, where the head of the hammer (the largest and heaviest part) represents the Earth. The handle represents the distance between the Earth and the Moon, as well as the mass of the Moon, itself.

If you try to balance the hammer on your finger, you'll see that the center of gravity isn't in the center of the hammer's head, but is somewhere between the center of the hammer's head and the bottom end of the handle. It's the same with the Earth-Moon "unit."

So, the Earth actually rotates on an axis other than the actual North-Pole-to-South-Pole axis; it rotates on what is called the "Barycenter." The Barycenter is the center of gravity of the Earth-Moon unit.

As the Moon revolves around the Earth, the Barycenter moves with it! Therefore, the axis on which the Earth rotates is constantly moving! And, since the Moon's orbit around the Earth is an oval, not a circle, the Barycenter moves in and out, along with the Moon's distance from the Earth. Note, though, that if we were to average the location of the Barycenter, the result is very close to the North-Pole-to-South-Pole axis.

Because the Barycenter is around 1,000 miles below the Earth's surface, that means that the side of the Earth that's opposite the Moon is travelling faster than the side of the Earth that faces the Moon. Therefore, there's a great centrifugal force on the Earth's side opposite the Moon. The Earth's rotational axis (running from the true North Pole to the South Pole) is sometimes shown as one that wobbles a bit.

This great centrifugal force throws the water outward on the side of the Earth opposite the Moon, creating the high tide on that side of the Earth — at about the same time as the high tide on the Moon-side of the Earth.

This far-side high tide, although high, is not as great as the high tide on the Moon's side of the Earth. Therefore, there is one "higher high tide" and one "lower high tide," as well as one "higher low tide" and "lower low tide" each day.

To complicate things even further, according to the US National Oceanic Service, there are over 30 variables in the Quoddy Loop which affect the amplitude of the tides, making tidal predictions a complex task!

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Area Tidal Wonders

Old Sow Whirlpool
Cobscook Reversing Falls
Great Tidal Range
Tide Sensing Stations
A Note About Tide Times

Visit our sister site
www.oldsowwhirlpool.com
Read the new (29 October 2003) Wired.com article about Old Sow Whirlpool Survivors' Association!

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Old Sow Whirlpool
Whirlpool Picture
©

Largest tidal whirlpool in the Western Hemisphere, Old Sow resides offshore between Deer Island, New Brunswick, and Dog Island, just off Moose Island in Eastport, Maine.

A local legend tells of a fisherman in a dingy who got caught in the maelstrom. His response...

"I didn't mind so much gettin' caught in it. What I resented was havin' to row uphill to get out!"

The Old Sow Whirlpool activity is tidal, so on each incoming and outgoing tide (about every 6 hours), the area comes alive with eddies, riptides, "boils" (upwellings), whirlpools, and -- rarely -- water fountaining 12' - 20' into the air!

The really large whirlpool (over 250-feet across*), however, is unpredictably occasional, probably due to the tidal dams that were build in the area during the Quoddy Tidal Power Project of the 1930s. Thus, a rare major funnel is more apt to appear when tides are running especially high, coinciding with strong winds.

* As determined in 1999 by the Old Sow Whirlpool Survivors' Association by measurement of smaller Old Sow activity via aerial photography. (See the larger aerial photograph of the Old Sow, with more information.)

Boat charters and excursions based out of Eastport, Deer Island, Campobello Island, and Lubec will sail through the Old Sow, upon request. For those willing to take the risk (generally safe in a motor-powered boat operated by a qualified captain), the Old Sow Whirlpool Survivor's Association makes Survival Certificates available (for a fee) to those who pass through the whirlpool and survive!

Many other small and medium size whirlpools can be seen in the area -- at Cobscook Reversing Falls, under the Roosevelt Memorial International Bridge at the Campobello-Lubec border, at the northern end of Indian Island (south of Deer Island, but this whirlpool can be seen well only by boat or plane), and at various other locations in the Quoddy Loop area.

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Cobscook Reversing Falls
©

Tides passing in and out over the rocky bottom in Cobscook Bay between Falls Island and Mahar Point in Pembroke, Maine, create an impressive waterfall effect.

Whirlpools can be seen, too. The tide here runs more than an hour later than the tide in Eastport (location of the closest tidal sensing station), so plan accordingly. (Other reversing falls exist in St. John, New Brunswick, in Sullivan, Maine, and elsewhere.)

This location is hazardous to boaters and is off limits to swimmers!

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Great Tidal Range
Good places to view the tidal range are just about any place that has a pier. Observe the water levels at high and low water (a six-hour interval). If you're boating, leave plenty of slack when tying up to the pier!

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Tide Sensing Stations
The closest tide sensing stations are at Eastport, Maine, and St. John, New Brunswick (see "Other Tides Resources," below for predictions for these two locations), thus, local published tide predictions are based on one of those locations. Generally speaking, the further to the northeast ("downeast") along the Fundy coast, the greater the tidal range.

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A Note About Tide Times
The tides are primarily caused by the Moon, so they are on "Moon Time." The moon circles the Earth about every 24 hours and 55 minutes (nearly 25 hours!), meaning that it rises about an hour later each day; therefore, the tides do the same thing--they are about an hour later every day!

In the Quoddy Loop area, there are two high and two low tides each day, for a total of four, with one exception--every several days only three tides will fit into that day, due to the Moon taking almost 25 hours to circle the Earth.

Tide prediction times for the Quoddy Loop area are either for Atlantic Time (New Brunswick, Canada) or Eastern Time (Maine, U.S.A.). (Atlantic Time is one hour ahead of Eastern Time: 1:00 AT = 12:00 ET.) Also, some published tide predictions do not correct for Daylight Saving Time. You may need to add or subtract an additional hour, depending upon your location and the tide prediction source.

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Quoddy Tidal Power Project

During Franklin Delano Roosevelt's presidency, hydroelectric engineer Dexter Cooper, who honeymooned on Campobello Island, observed the massive amounts of seawater (70 billion cubic feet) entering Passamaquoddy Bay with each incoming tide. Dexter got the idea of harnessing the tide's energy to produce electricity. Cooper was successful in enlisting the U.S. federal government in funding the project.

Cooper's idea was to dam off both Passamaquoddy Bay and Cobscook Bay. The incoming tide would be trapped by gates and dams in Passamaquoddy Bay. Then, the water would be allowed to escape through turbine generators located at the isthmus on Moose Island, Eastport, with the water escaping into Cobscook Bay, where it would be held until low water. At that point, the water would be let out into the Bay of Fundy via another set of gates.

The project was begun, headquartered at Quoddy Village, Eastport, with tidal dikes built between Treat Island (Eastport) and Dudley Island (Lubec), and from Pleasant Point Passamaquoddy Reservation out to Carlow Island (Eastport) and then on to Moose Island, Eastport. Other dikes were planned, but were never constructed.

The dike between Treat and Dudley islands can easily be seen at low water. Dikes built between Pleasant Point Passamaquoddy Reservation and Carlow Island, Eastport, and from Carlow Island to Moose Island, Eastport, form the causeway supporting Route 190 in that location.

U.S. national politics ended the funding for the project, although attempts were made--through President Eisenhower's term in office--to revive it. While still technically feasible, the project is seen as impracticle, considering the impact on the fishery and environment, along with current costs for completing the project.

Cooper's plan included using electric power to smelt ore that is available in the area. Had the project been completed, the local economy and environment would be considerably different than it is today.

The Quoddy Maritime Museum, which opened in July of 1999 in Eastport, houses a working scale model of the Passamaquoddy Bay Tidal Power Project which was built for the original project. The model, formed of concrete and weighing thousands of pounds, shows the locations of the proposed dikes and gates, as well as the turbine-powered generating station. When operating, you can observe how the tides flow into the area's bays, and how these tides could have been harnessed to generate electricity.

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Other Tides Resources

Canadian Tides, Currents & Water Levels
Tide Predictions: Eastport, Maine

Tide Predictions: St. John, New Brunswick

Cape Cod Radio Mystery Theater has produced an hour-long thriller, entitled The Whirlpool, on CD about the Old Sow. The CD is available at select shops in the Quoddy Loop.

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Copyright Notice

Photographs by Robert Godfrey © 1995 Old Sow Publishing

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