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The difficulties of rescue by operations from the shore are greatly increased in cases where the anchors are let go after entering the breakers, as is frequently done, and the chances of saving life correspondingly lessened.

Number.

Name of station.

State.

Locality.

161 Cape Henry. 162

Virginia Beach 163 Dam Neck Mills, 164 Little Island. 165

False Cape. 166 Wash Woods 167

Penneys Hill. 168

Currituck Beach. 169 Poyners Hill. 170 Catfeys Inlet.. 171 Paul Gamiels Hill 172 Kitty Hawk. 173 Kill Devil Hills. 174 Nags Hea 175 Bodie Island. 176 Oregon Inlet. 177 Pea Island.. 179 Chicamscomico. 180 Gull Shoal.. 181 Little Kinnakeet. 182 Big Kinnakeet. 183 Cape Hatteras. 184 Creeds Hill. 185 Durants. 186 Hatteras Inlet.. 187 Ocracoke. 188 Portsmouth. 189

Core Bank.. 190 | Cape Lookoout. 191 Fort Macon... 192 Bogue Inlet. 193 Cape Fear. 194 Oak Island 196 Sullivans Island. 202

Bulow 1 203 Mosquito Lagoon 1.. 204 Chester Shoal 1. 205 Bethel Creek 1 206 Indian River Inlet 1. 207 Gilberts Bar 1 208 Fort Lauderdale 1 209 Biscayne Bayi

V&.... mile southeast of lighthouse.
Va.. miles south of Cape Henry light.
Va. 9 miles south of Cape Henry light.
Va. On beach abreast of North Bay.
V& On beach abreast of Back Bay.
N.C... On beach abreast of Knotts Išland.
N.C... 5 miles north of Currituck Beach light.
N.C... } mile south of Currituck Beach light.
N.C... 6 miles south of Currituck Beach light.
N.C... 91 miles south of Currituck Beach light.
N.C...4 miles north of Kitty Hawk.
N.C... On beach abreast north end of Kitty Hawk Bay
N.C... 4 miles south of Kitty Hawk.
N.C... 8 miles north of Oregon Inlet.
N.C... | mile northeast of Bodie Island light.
N.C... mile south of Oregon Inlet.
N.C... miles north of New Inlet.
N.C... 41 miles south of New Inlet.
N.C... 10 miles south of New Inlet.
N.C... 10 miles north of Cape Hatteras light.
N.C... 5 miles north of Cape Hatteras light.
N.O... 1 mile south of the lighthouse.
N.C... 31 miles west of Cape Hatteras light.
N.C... 24 miles east of Hatteras Inlet.
N.C... 14 miles west of Hatteras Inlet.
N.C... 22 miles northeast of Ocracoke Inlet.
N.C... Northeast end of Portsmouth Island.
N.C... Halfway between Ocracoke Inlet and Cape Lookout.
N.C... 11 miles south of the lighthouse.
N.C... Beaufort entrance, 4 mile north of fort.
N.C... mile east of inlet.
N.C... On Smith Island, Cape Fear.
N.C... West side mouth of Cape Fear River.
S.C...At Moultrieville, at north end of harbor jetty.
Fla... 174 miles south of Matanzas Inlet.
Fla... On beach outside the lagoon.
Fla.

94 miles north of Cape Canaveral.
Fla..

14 miles north of Indian River Inlet.
Fla. South side of inlet.
Fla..

St. Lucie Rocks, 2 miles north of Güberts Bar Inlet.
Fla.

31 miles north of New River Inlet.
Fla.. 41 miles north of Miami entrance.

House of refuge.

VARIATION OF THE COMPASS.

The magnetic variation for 1923, and annual increase or decrease at points mentioned, are as follows:

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Increase, 3'.

Do. Increase, 2'.

Do. Increase, 1'.

Off Cape Henry (10 miles).
Off Cape Hatteras (12 miles)
Off Cape Lookout (15 miles).
Off Cape Fear (15 miles).
Off Charleston Entrance.
Off Savannah (on bar).
On Doboy Sound bar.
St. Johns River (outside jetties).
Off Cape Canaveral (12 miles).
At Fowey Rocks light...
At Alligator Reef light.
At Sombrero Key light..
At Sand Key light..
At Rebecca Shoal light...
Hole in the Wall (Bahamas).
At Great Isaac light (Bahamas).
On Salt Key Bank (north of Cuba).
Middle of Albemarle Sound (off Bull Bay).
Middle of Croatan Sound.
Middle of Pamlico Sound (north of Ocracoke).

6° W.
57° W.

W.
38 w.
1° W.

1° E.
° E.
1° E.
11. E.
26 E.
27° E.
21° E.
21° E.

Increase, 1'

Do. Do. Do. Do.

how. jo E.

1° E. 51° W. 53° W. 50 W.

Increase, 3'.

Do. Do.

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1 Tide tables for the Atlantic coast of the United States, published annually by the Coast and Geodetic Survey, predicting the tiines and heights of tides for every day of the year, at all the principal ports, can be obtained from the agents; price, $0.15. 2 The mean lunitidal interval for high water or for low

water is the average timefrom the meridian transit of the moon to the next following high or low water, respectively; it is also called the corrected establishment.

CURRENTS, CAPE HENRY TO KEY WEST.

From our present information the indications are that, except during northerly and northeasterly winds, a current of about 0.5 knot, setting northeastward with the trend of the coast, may be expected outside the 10-fathom curve as far north as Cape Hatteras, and that it increases offshore toward the axis of the Gulf Stream.

Strong currents are produced by the wind along the coast in northeasterly and southerly gales, reversing or greatly accelerating the normal current. Their strength and set depend on the direction, strength, and duration of the gale. A table showing the direction and velocities of the currents that may be expected with winds of given strength is given on page 36.

Current tables for the Atlantic coast, giving the time of turning of the current for every day of the year at a number of stations, including Chesapeake Bay Entrance, Charleston Harbor Entrance, and Savannah River Entrance, are published annually in advance by the Coast and Geodetic Survey. These current tables are for sale at 10 cents per copy, and may be obtained from any of our sales agencies or direct from this Office.

The following is a more detailed statement of the currents along the coast.

Diamond Shoal light vessel (off Cape Hatteras, N. C.).—The tidal current here is rotary, turning clockwise, but very weak, the velocity of the current at time of strength being less than a tenth of a knot. The currents encountered off Cape Hatteras are therefore nontidal and depend chiefly on the wind. Winds from the southwest, south, and southeast directions bring about the strongest currents which set northeasterly, a wind of 35 miles per hour bringing about a current of 114 knots. Winds from the northeast and northwest are only about 70 per cent as effective in producing currents, a wind of 35 miles per hour from the northeast or northwest bringing about a southerly current of about 0.7 knot.

Cape Lookout Shoals (off Cape Lookout, N. C.).—The tidal current here is rotary, turning clockwise. The strength of the flood current occurs about two hours before the current turns west in the entrance to Chesapeake Bay and sets N. 85° W., with a velocity of 0.3 knot. The strength of the ebb current comes about two hours before the current turns east in the entrance to Chesapeake Bay and sets S. 85° E., with a velocity of 0.25 knot. The minimum currents before flood and ebb are very small, being less than 0.1 knot. Since the tidal current here is weak, the currents brought about by the winds completely mask the tidal currents. In general, the current appears to set northeasterly in the summer months and southerly during the winter months, with an average velocity of 0.25 knot.

Frying Pan Shoals light vessel (off Cape Fear River, N. C.).—The tidal current here is rotary, turning clockwise. The strength of the flood current occurs about one hour after the current turns west in the entrance to Charleston Harbor and sets N. 55o W., with a velocity of 0.4 knot. Strength of ebb comes about one hour after the current turns east in the entrance to Charleston Harbor and sets S. 65o E., with a velocity of 0.4 knot. The minimum current before flood comes about two hours before the current turns west in the entrance to Charleston Harbor setting southwesterly with a velocity of 0.25 knot. The minimum current before ebb comes about two hours before the current turns east in the entrance to Charleston setting northeasterly with a velocity of 0.25 knot.

Charleston light vessel (off the entrance to Charleston Harbor, S. C.).—The current is rotary, turning clockwise. The strength of the flood current occurs about one hour after the current turns west in the entrance to the Charleston Harbor and sets N. 80° W., with a velocity of 0.3 knot. The strength of the ebb current comes about 112 hours after the current turns east in the entrance to Charleston Harbor and sets S. 80° E., with a velocity of 0.3 knot. The minimum currents before flood and ebb set southerly and northerly, respectively, with a velocity of 0.15 knot.

Martin's Industry gas and whistling buoy (off the entrance to Port Royal Sound, S. C.).—The current here is rotary, turning clockwise. The strength of the flood current occurs about 212 hours after the current turns west in the entrance to the jetties of the Savannah River and sets N. 75o W., with a velocity of 0.6 knot. The strength of the ebb current comes about three hours after the current turns east in the entrance to the jetties of the Savannah River and sets S. 75o E., with a velocity of 0.6 knot. The minimum currents before flood and ebb set southerly and northerly, respectively, with the velocity of 0.15 knot.

Brunswick light vessel (off the entrance to St. Simon Sound, Ga.). The tidal current is rotary, turning clockwise. The strength of the flood current occurs about three hours after the current turns west in the entrance to the jetties of the Savannah River and sets N. 60° W., with a velocity of 0.5 knot. The strength of the ebb current comes about 31/2 hours after the current turns east in the entrance to the jetties of Savannah River and sets S. 60° E., with a velocity of 0.5 knot. The minimum currents before flood and ebb set southerly and northerly, respectively, with velocities of about 0.15 knot.

THE GULF STREAM.

The Gulf Stream sets eastward and northward through the Straits of Florida, and after passing between Fowey Rocks and Little Bahama Bank it continues northward and then northeastward, following the general direction of the 100-fathom curve. The axis of the Gulf Stream, or line of greatest velocity, lies from 10 to 20 miles eastward of the 100-fathom curve. Between Cuba and Florida Reefs, off Habana, the axis of the stream is nearer the Cuban coast; but after making the bend between Salt Key Bank and Florida Reefs the axis of the stream approaches the coast of Florida and lies from 4 to 11 miles outside the 100-fathom curve.

Northward of the West India Islands there is another stream, which, driven by the trade winds, is moving westward. This is a slow current, but where it joins the Gulf Stream proper at about latitude 30° N. it materially adds to the latter on its way toward the northern seas.

Off Cape Hatteras the width of the Gulf Stream is about the same as when it leaves the Straits of Florida. However, it is more liable to fluctuations in direction, particularly along the edges, and in its progress northward and eastward, by the time the Newfoundland banks are reached, it is probable that these fluctuations entirely obiiterate the stream as a body distinguishable from its mate which has come by the outside passage from the trade region. In these latitudes, however (about 40° N.), the whole surface is slowly moving eastward, driven by the prevailing westerly winds. The investigations of the Gulf Stream indicate that there is no way of utilizing the thermometer to determine with certainty the direction of the current.

A steamer bound from Cape Hatteras to Habana or the Gulf ports crosses the stream off Cape Hatteras. A fair allowance to make in crossing the stream is 112 knots in a northeasterly direction for a distance of 40 miles from the 100-fathom curve. In the run from the southern edge of the stream to Matanilla Shoal no allowance for current can be given.

Crossing the Gulf Stream at Jupiter or Fowey Rocks an average allowance of 212 knots in a northerly direction should be made for the set of the current. The weakest current will be experienced about three hours before the transit of the moon.

Crossing the stream from Habana a fair allowance for the average current between 100-fathom curves is 1.1 knots in an east-northeasterly direction.

In the straits of Florida the velocity of the stream is affected by the winds, by differences in barometric pressure inside the Gulf of Mexico and outside, and by the tides. The first two causes produce the largest changes and are difficult to estimate. The effect of the tides on the stream amounts to about 0.5 knot, the maximum current of the Gulf Stream occurring three hours after the moon's meridian transit (upper or lower) and the minimum current three hours before the moon's transit. Outside of the straits of Florida the velocity of the stream is affected principally by the winds.

The mean surface velocity of the Gulf Stream is 3.5 knots at a point 111/2 miles east of Fowey Rocks and 2.2 knots at a point 60 miles south of Rebecca Shoal. These points are on the axis of the

stream, or where the current is a maximum, the velocity of the stream decreasing gradually from these central points as the edges of the stream are approached. These velocities are affected considerably by prevailing winds.

The mean position of the axis of the Gulf Stream, or the point where the greatest velocity may be found, is given in the following table:

Miles.
East of Contoy Island, Yucatan.--

35
North of Habana...

25 East of Fowey Rocks_

11 East of Jupiter Inlet lighthouse.

19 Southeast of Cape Hatteras lighthouse--

31 In the straits of Florida, between Rebecca Shoal and Cuba, the following table gives the surface velocity of the Gulf Stream at five stations:

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Between Fowey Rocks and Gun Key, in the straits of Florida, the following table gives the surface velocity of the Gulf Stream at six stations:

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In this table are given the results of recent investigations on the currents caused by local winds. These investigations are based on observations made on a number of the light vessels along the Atlantic coast from Nantucket Shoals light vessel to Brunswick light vessel. The results therefore apply more directly along the route between light vessels, but are applicable also to the coastal sailing routes farther offshore.

Direction of current due to wind. It is evident that a wind continuing for some time will give rise to a current the velocity of which increased with an increase in the velocity of the wind, and the mariner has taken it for granted that this current brought about by the wind sets in the same direction as the wind, but the results of

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