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Stellwagen Bank lies northward of Cape Cod and off the entrance to Massachusetts Bay; the least found depth over it is from 912 to 20 fathoms (17.4 to 37 m.), but fishermen have reported a depth of 7 fathoms (12.8 m.) at the north end.
Grand Manan Channel. This channel leads along the coast of Maine, between it and Grand Manan Island, and is an approach from westward to Quoddy Roads and Passamaquoddy Bay, and the most direct passage for vessels bound up the Bay of Fundy from along the coast of Maine. The channel varies in width from 51/2 miles abreast Campobello Island to 10 miles abreast Southwest Head, the southwestern point of Grand Manan Island. Its western approach is marked by Machias Seal Island Lighthouse, which also marks the westernmost of the rocks and ledges which lie southwestward of Grand Manan Island. With the exception of the dangers between Machias Seal Islands and Grand Manan Island, the channel is free and has a good depth of water. The tidal currents have a velocity of 212 to 3 knots and follow the general direction of the channel. Off West Quoddy Head the currents set in and out of the roads, forming strong rips. Sailing vessels should not approach West Quoddy Head too closely with a light wind.
CURRENTS, GULF OF MAINE
Offshore.-The current over the region extending westward and northward of a line from Georges Bank to Lurcher Shoal is very nearly simultaneous. The flood current sets northward, the strength of the flood over the eastern portion of this region occurring about 2 hours after the current turns northward in Bay of Fundy entrance (about 3 hours after the time of Boston low water), and over the western portion about 12 hour later. The ebb current sets southward, the strength of the ebb over the eastern portion occurring about 2 hours after the current turns southward in Bay of Fundy entrance (about 3 hours after the time of Boston high water) and over the western portion about 12 hour later.
Slack water over the eastern portion occurs about 1 hour before the current turns southward and northward in Bay of Fundy entrance (about the time of high and low water at Boston), and over the western portion about 12 hour later.
Off Nova Scotia, outside the 50-fathom (91 m.).curve, the velocity at the time of strength is about 11/2 knots; inside the 50-fathom (91 m.) curve the velocity is between 112 and 21,2 knots.
At the entrance of the Bay of Fundy, 5 miles southeastward of Gannet Rock, the strength of the flood current occurs about 3 hours after the current turns north ward in the Bay of Fundy entrance (about 3 hours before high water at St. John, New Brunswick), has an average velocity of 2.7 knots, and sets 36° true (NE. by E. mag.).
The strength of the ebb occurs about 3 hours after the current turns southward in the Bay of Fundy entrance (about 3 hours before low water at St. John), has an average velocity of 3.9 knots, and sets 228° true (WSW. mag.).
Slack water before the flood occurs about the time of the corresponding slack at Bay of Fundy entrance (about 12 hour after low water at St. John). Slack water before the ebb occurs about 12 hour
before the corresponding slack at Bay of Fundy entrance (about the time of high water at St. John).
In the Bay of Fundy slack water before the flood occurs 1/2 hour after the current turns northward in Bay of Fundy entrance (about 34 hour after low water at St. John). Slack water before the ebb occurs about 1/4 hour after the current turns southward in Bay of Fundy entrance (about 34 hour after high water at St. John). The velocity at strength is between 142 and 21/2 knots, the flood setting northeastward and the ebb southwestward.
In Grand Manan Channel the average velocity at strength is about 21/2 knots, the flood setting northeastward and ebb southwestward, approximately parallel to the channel. Slack water before the flood occurs at about the time of low water at St. John, and slack water before the ebb about 1/2 hour after high water at St. John. The predicted times of slack water for every day in the year are given in the Atlantic Coast Current Tables.
Over Georges Bank the velocity at strength is about 2 knots.
Between Georges Bank and Brown Bank the velocity at strength is about 11,2 knots, with a like velocity between Brown Bank and Cape Sable Bank.
Over Stellwagen Bank, and in the channel between it and Cape Cod, the flood current sets westward and the ebb northeastward to eastward. The flood current begins about 1/2 hour before the corresponding slack at Boston Harbor (about the time of low water at Boston), and the ebb current begins about 1/2 hour before the corresponding slack at Boston Harbor (about high water). The velocity at strength is about 34 knot.
Alongshore.—On the coast of Maine eastward of Portland the flood sets eastward and has greater velocity than the ebb, which sets westward. In passing from one headland to another it is always necessary to make allowance for the current setting into or out of the bays or rivers, according to the stage of the tide; such allowance frequently amounts to as much as 12 point.
Eastward of Mount Desert the currents have a greater velocity than farther west, but are more regular in their ebb and flow, conforming more exactly to the rise and fall of the tides. Along the coast between Mount Desert and Portland the effect of the westerly (ebb) set is more marked as compared with the flood than is the case farther east.
With easterly or southeasterly winds the currents have more of a tendency on shore than at other times, but they are not affected much by northerly, westerly, or southerly winds.
No systematic current observations have been made along the coast of Maine, except at Portland lightship.
Portland Lightship.—The tidal current is weak, being on the average less than 14 knot at time of strength. During October, November, and December there is a southerly set of about 1/2 knot. Southerly winds, however, tend to reverse this set. The greatest velocity observed was 1.6 knots westerly, accompanied by an easterly wind of 35 to 40 miles per hour.
Boston Lightship.-- The tidal current is small, averaging about 14 knot at time of strength. Strength of flood current occurs about
3 hours after the current turns westward at Deer Island light (about 234 hours before high water), and sets 265o true (W.78 N. mag.). Strength of ebb occurs about 3 hours after the current turns eastward at Deer Island Light (about 234 hours before low water at Boston), and sets 85° true (E. 7. S. mag.).
Because of the weak character of the tidal currents the winds greatly influence the direction of the current. The greatest velocity observed during summer and autumn was less than i knot.
The currents along the eastern side of Cape Cod and across Monomoy and Nantucket Shoals are described in Atlantic Coast Pilot, Section B.
APPROACHING OR STANDING ALONG THE COAST OF MAINE EAST
WARD OF PORTLAND
This section of the coast is a dangerous one for navigators on account of the strong tidal currents, frequent fog, and numerous offlying dangers. For information concerning currents see page 30. and for information concerning fog see page 8 and the meteorological tables in the appendix. The lead is of little assistance to locate the position, but should be in constant use to prevent too close an approach to dangers. See a discussion of the character of the bottom on page 28.
Wrecks.-An examination of the record of wrecks occurring on the coast of Maine eastward of Portland shows that wrecks have occurred on practically all of the offlying islands and rocks between Portland and Machias Bay, most of them in thick weather, either fog or snow. Many of the wrecks could have been prevented if frequent soundings had been taken.
During thick weather great caution is necessary when approaching the coast, especially eastward of Petit Manan, where the tidal currents have considerable velocity. If one of the offshore lighthouses has not been made and the position accurately determined before the fog shuts in, it is advisable to keep well outside until it clears. East of Seguin Island, except southward and eastward of Grand Manan Island, in clear weather the land will always be made before any of the outlying dangers are encountered, and by keeping 3 miles outside of the headlands and outlying islands vessels will clear all unmarked dangers.
Coming from the vicinity of Cape Sable.- Vessels bound to Machias or ports eastward of it should make Machias Seal Island Lighthouse and pass westward of it. If bound to Eastport or Calais, the route through Grand Manan Channel is preferable to passing eastward of Grand Manan, as in case of bad weather coming on an anchorage may be made either at Little River or in Machias Bay.
It is not advisable for a stranger to pass eastward of the Machias Seal Islands or between them and Grand Manan, where there are a number of ledges on which the sea breaks in heavy weather, including Bull Rock, an unmarked danger with 2 feet (0.6 m.) over it.
If bound to ports in Penobscot Bay, vessels should steer so as to make either Mount Desert Lighthouse or Matinicus Rock Lighthouse. In the former case, on a clear day, Cadillac Mountain, the highest part of Mount Desert Island, may be sighted before the lighthouse. When steering for Matinicus Rock Lighthouse, Isle au Haut, 556
feet (169 m.) high, on a clear day may be sighted about the same time as the rock.
Coming from the vicinity of Cape Cod or Cape Ann.-Vessels, both steamers and large tows, bound into Penobscot Bay, including those coming from Boston and Cape Cod Canal, and also those passing eastward of Cape Cod, usually make the gas and whistling buoy off Cape Ann and then shape the course for Manana Island gas and whistling buoy and enter through Twobush or Muscle Ridge Channels. In the winter and in bad weather the smaller class of vessels follow the coast, sighting the principal lighthouses, and making an anchorage on approach of bad weather. Vessels bound from Cape Cod or Cape Ann to points eastward of Penobscot Bay usually shape the course from Cape Ann to either Monhegan Island or Matinicus Rock Lighthouses.
On all the banks in or near the Gulf of Maine a number of fishing vessels
be found at anchor. They are sometimes very numerous in the South Channel, on the Georges Bank, and Jeffrey Ledge. In the summer a large fleet of mackerel fishermen will often be met near the coast between Mount Desert Rock and Cape Ann.
Standing along the coast.-In clear weather, vessels stand along the coast close enough to make the lighthouses and to recognize the principal landmarks on shore. In thick weather they aim to make the fog signals or the whistling or bell buoys; these buoys are placed close enough to one another and to the fog signals to be readily followed by vessels if not set too much off their course by the tidal currents. When running in thick weather a vessel should verify her position as often as possible by the aids, and when approaching a fog signal or buoy should proceed slowly, using the lead, and if necessary stop until the looked-for aid is found and recognized before she continues for the next aid. There are three good harbors for which a stranger standing along the coast in their vicinity can make in thick weather and enter with ordinary precaution-Machias Bay, Winter Harbor, and Boothbay Harbor.
Vessels equipped with radio should make use of the radiocompass stations as listed on page 17. In addition to this list, the Canadian Government maintains radiocompass stations at Yarmouth and St. John, New Brunswick.
APPROACHING OR STANDING ALONG THE COAST BETWEEN PORT
LAND AND CAPE COD
Approaching Massachusetts Bay from sea.—The approach to the coast of Massachusetts north of Cape Cod is through the Gulf of Maine, the body of water lying westward of a line drawn from Cape Cod to Cape Sable. Between these points, and forming the southeastern limit of the Gulf, lie Nantucket Shoals, Georges Bank, and Brown Bank, areas over which there is a depth of less than 50 fathoms (91 m.). Nantucket Shoals and Georges Bank, on account of their many shoal spots and the strong tidal currents setting over them, are a menace to navigators approaching the coast or standing from Canadian ports to New York.
As far as the navigator is concerned, Brown Bank need not be avoided; it may even assist, from soundings, to approximately locate a vessel's position.
The part of Georges Bank lying between latitude 41° 05' N., and 42° 00' N., and longitude 67° 17' W. and 68° 35' W. should be avoided; in heavy weather the sea breaks on the spots with 10 fathoms (18.3 m.) or less, and strong tide rips are encountered, the latter, however, not always indicating shoal water, For current information see page 31.
Vessels passing south of the dangerous part of Georges Bank should not shoal the water to less than 25 fathoms (46 m.). Approaching this part of the bank from eastward or southward, the water shoals gradually. Approaching from westward, the depths are irregular and the water shoals abruptly in places to 20 fathoms (37 m.) or less. On the north side of Georges Bank, between longitude 66° 00' W. and 68° 00' W., the 100-fathom and 50-fathom (91 and 46 m.) curves are but a few miles apart, and when approaching the dangerous part of the bank from northward 50 fathoms (91 m.) may be taken as a good depth to avoid the shoals.
The only known outlying danger in the Gulf of Maine to be avoided by vessels bound to ports in Massachusetts is Ammen Rock, with 414 fathoms (7.6 m.), in latitude 42° 53' N. and longitude 686 55' W. It is a part of Cashe Ledge, which is about 612 miles long in a north-northeast direction, with depths less than 30 fathoms (55 m.).
Vessels from ports in northern Europe or the British Provinces and bound to ports in the United States north of Cape Cod approach the coast passing between Cape Sable and Georges Bank, between latitude 42° 00' N. and 43° 10' N. If bound to Boston, they cross Brown Bank and shape the course for Boston Lightship. See page 269.
Vessels approaching the Gulf of Maine from southward sometimes endeavor to make the 50-fathom (91 m.) curve on the southern edge of Georges Bank, in latitude 40° 20' N. and longitude 68° 50' W., then stand 0° true (N. by E. 14 E. mag.) on soundings of over 30 and less than 50 fathoms (55 and 91 m.) for about 50 miles, and then shape a 323° true (NNW. mag.) course, taking care to keep in a greater depth than 20 fathoms (37 m.) until the course is laid to sight Cape Cod Lighthouse. This lighthouse, Nauset Beach Lighthouse, the skeleton radio towers, and the Pilgrim Monument at Provincetown are the most prominent marks on Cape Cod.
The passage across Georges Bank between the easternmost of the Nantucket Shoals and the westernmost shoal spots of Georges Bank, about 30 miles wide, has been called Great South Channel.
Vessels coming from Cape Hatteras, Chesapeake Bay, Delaware Bay, or New York make Nantucket Shoals Lightship.
Vessels of less than 24 feet (7.3 m.) draft may, when coming from southward or alongshore, enter the Gulf of Maine through Vineyard and Nantucket Sounds. This route avoids Nantucket Shoals, and is the one followed by vessels in the coasting trade. Vessels of 22-foot (6.7 m.) draft or less can also enter through Cape Cod Canal. (See p. 299.) .
Directions for all of the various routes from southward to the north end of Cape Cod are given in Atlantic Coast Pilot, section B, Cape Cod to Sandy Hook.