but the strength of the offshore current is not affected until within a few miles of the mouth.

Wind currents.-Moderate to heavy winds set up strong currents in a direction about 20° to the right of the wind, reversing or greatly accelerating the normal currents; in fact, the principal currents along this stretch of coast, when away from the larger bays, are the wind currents. Their strength and set depend on the direction, strength, and duration of the wind. The greatest observed velocities of the current at the lightships are Ambrose Channel, 1.4 knots; Northeast End, 1.2 knots; Overfalls, 3.6 knots; Winter Quarter, 0.8 knot; Fenwick Island, 2 knots; and Tail of the Horseshoe, 2.8 knots. These results are for three winter months, and probably closely approximate the maximum which might be expected.

Offshore currents. Observations made offshore have developed the existence of weak tidal currents, veering around the compass, similar in character to those inshore, although of less strength. These are accompanied by a general drift in a southerly to southwesterly direction, amounting to about 1/4 of a knot; this extends from about the 20-fathom curve out nearly to the Gulf Stream.

The following is a more detailed statement of the observations at each lightship. The wind currents are of more importance than the tidal currents, and the two must be combined in making allowance for set.

Ambrose Channel Lightship. The tidal currents have a mean velocity of about 1/4 knot at strength of flood or ebb, the flood setting in a westerly and the ebb in an easterly direction. The strength of flood occurs about 14 hours before time of high water at Sandy Hook, and the strength of ebb about 14 hours before time of low water at Sandy Hook. Wind velocities of 10 to 25 miles produce currents of about 0.5 to 1 knot, setting about 20° to the right of the wind. The greatest observed velocity of the current was about 1.4 knots during a gale.

Northeast End Lightship.-The tidal currents have a mean velocity of 14 knot at strength of flood or ebb, the flood setting in a northwesterly and the ebb in a southeasterly direction. The strength of flood occurs about 111⁄2 hours earlier than the strength of flood at Overfalls Lightship (or about 211⁄2 hours earlier than the time of high water at Sandy Hook). The strength of ebb occurs about 1 hour earlier than the strength of ebb at Overfalls Lightship (or about 24 hours earlier than the time of low water at Sandy Hook). Wind velocities of 10 to 30 miles produce currents of about 0.5 to 0.9 knot, setting about 20° to the right of the wind. The wind current must be combined with the tidal current in making an allowance for set. The greatest observed velocity of the current was 1.2 knots during a 50-mile-an-hour gale.

Overfalls Lightship. See currents, Delaware Bay.

Fenwick Island Lightship. The tidal currents have a mean velocity of about 1/4 knot at strength of flood or ebb, the flood setting in a northerly direction and the ebb in a southerly direction. The strength of flood occurs approximately at the same time as at Overfalls Lightship (or about 1 hour before the time of high water at Sandy Hook), and the strength of ebb occurs approximately at the same time as at Overfalls Lightship (or about 1 hour before the time

of low water at Sandy Hook). Wind velocities of 10 to 30 miles produce currents of about 0.5 to 1 knot, setting about 20° to the right of the wind. This wind current must be combined with the tidal current in making an allowance for set. The greatest observed velocity of the current was 2 knots during a 60-mile-an-hour gale. Winter Quarter Shoal Lightship.-The tidal currents have a mean velocity of about 0.1 knot at strength of flood or ebb, the flood setting in a southwesterly direction and the ebb in a northeasterly direction, occurring 134 hours after the time of low water and high water, respectively, at Sandy Hook. Wind velocities of 15 to 30 miles produce currents of about 0.3 to 0.6 knot, setting about 20° to the right of the wind. The greatest observed velocity of the current was 1.0 knot.

Current tables.-Current tables, published annually in advance, give a great deal of useful information relative to currents along the coast and in Delaware and Chesapeake Bays. They are for sale by any of the sales agents or at the Coast and Geodetic Survey Office, Washington, D. C., price 10 cents.

INLAND WATERWAYS

The following data about the inland waterways are included for ready reference:

The inland waters extending eastward from New York include Long Island Sound, Narragansett Bay, Buzzards Bay, and Vineyard and Nantucket Sounds. From the head of Buzzards Bay there is an available passage through Cape Cod Canal, from which the passage to the New England coast must be made mostly outside although there are harbors at short intervals.

Long Island Sound has harbors at short intervals on both sides from its west end to Eatons Neck, and thence on its north side to and including Fishers Island Sound. From Watch Hill boats must go outside to the bays and sounds eastward, but Point Judith Harbor of Refuge is available, and shortens the distance between harbors.

On the south coast of Long Island there is at present no inside route between Jamaica Bay and the inland waters eastward. Boats must go outside from New York to East Rockaway Inlet, and the latter requires local knowledge, because of frequent changes. But from East Rockaway Inlet boats of 5 feet (1.5 m.) draft can be taken inside through Great South Bay and 3 feet (0.9 m.) draft through Moriches and Shinnecock Bays and Shinnecock Canal to Great Peconic Bay. Masted boats are limited to a.height of less than 20 feet (6.1 m.) above the water by the fixed bridges over Shinnecock Canal, and otherwise all bridges have draw openings. This route is described in Coast Pilot, Section B, under the heading "Inland waters, south coast of Long Island.”

By the Hudson River and Erie Canal boats can be taken from tidewater of the Hudson at Troy into the Great Lakes. There are 35 locks, and the distance from Troy to Tonawanda on the Niagara River is 290 miles. The controlling depth is 12 feet (3.6 m.), and the usable lock dimensions are 300 feet long and 44 feet wide; the lifts range from 6 to 401⁄2 feet. By the Hudson River and Champlain Canal vessels can be taken from tidewater of the Hudson River at Troy into Lake Champlain. There are 11 locks of the same di

mensions as given for the Erie Canal. The principal ports on the lake are Port Henry, N. Y., near the south end; Burlington, Vt., and Plattsburgh, N. Y., near midlength; and Rouses Point, N. Y., near the international boundary. Vessels can pass from Lake Champlain into the St. Lawrence River, at Sorel, 30 miles below Montreal, through the Richelieu River and Chambly Canal. The limiting dimensions of the smallest lock are 118 feet (110 feet available), 222 feet wide. The limiting depth is 612 feet (1.9 m.) at low water. There are nine locks in the canal and one at St. Ours, 12 miles above Sorel. The total distance from Lake Champlain (international boundary) is 69 miles.

Charts may be obtained from the New York State Superintendent of Public Works, Albany, N. Y., covering the canals in New York State, and charts of the natural navigable waters embraced in the canal system may be had from the United States Lake Survey, Detroit, Mich.

The nearest inlet connecting with the inside waters on the coast of New Jersey is nearly 45 miles southward of Sandy Hook (Barnegat Inlet), and boats must pass outside between these points, unless taking the route through the Delaware & Raritan Canal. But from the head of Barnegat Bay to Cape May Harbor there is an inside route for boats of 6 feet (1.8 m.) draft by taking advantage of the tide in places.

There is an inside route, good for small boats, 1 foot (0.3 m.) draft at high water, along the coast of Delaware, Maryland, and Virginia, from Delaware Bay southward to Cape Charles.

New York to Key West.-Vessels of 7 feet (2.1 m.) draft can pass inside from New York Bay to Delaware River through the Delaware & Raritan Canal. Masted vessels are limited to a height of 50 feet above canal level by a bridge without draw at New Brunswick, N. J.

Vessels of 10 feet (3.0 m.) draft can pass inside from Delaware River to Beaufort, N. C., through the Chesapeake & Delaware Canal, Chesapeake Bay, Elizabeth River, Albemarle & Chesapeake Canal, Albermarle and Pamlico Sounds or the Alligator River-Pungo River Canal, Neuse River, Adams Creek, canal to Core Creek, and Newport River. A draft of 3 feet (0.9 m.) can be taken inside about 40 miles southward from Beaufort, N. C., to New River Inlet. All bridges have draw openings.

There is no inside passage from Beaufort, N. C., to Winyah Bay, a distance of about 163 nautical miles, and vessels must pass outside between these points. Cape Fear River, halfway between them, is available as a harbor.

Vessels of 5 feet (1.5 m.) draft can pass inside from Winyah Bay, S. C., to St. Johns River, Fla. All bridges have draw openings. Vessels of 3 feet (0.9 m.) draft can pass inside from St. Johns River to Miami, Fla., through Pablo Creek, North Matanzas, Halifax, and Hillsborough Rivers, Mosquito Lagoon, Indian River, South Jupiter Narrows, Hobe and Jupiter Sounds, Lake Worth, Key Biscayne Bay, and the canals connecting them. All bridges have draw openings.

From Miami to Key West, Fla., there is practically an inside route through the Hawk Channel that can be used by vessels of 10

feet (3.0 m.) draft. Cuts with a depth of 5 feet (1.5 m.) have been made in places so that vessels of 4 feet (1.2 m.) draft can go from Miami through Key Biscayne Bay, Card Sound, Barnes Sound, railroad drawbridge at Cross Key, Blackwater Sound, Tarpon Basin, Florida Bay along the north side of the keys to Long Key, and thence northwestward into the Gulf of Mexico at Cape Sable, or can continue in Florida Bay along the north side of the keys, through Big Spanish Key Channel, and thence in the Gulf of Mexico to Key West.

Boats of 3 feet (0.9 m.) draft can be taken across Florida by way of North New River Canal to Lake Okeechobee. West of there the route is closed, due to damage to a lock at Fort Thompson in 1926, which has not been repaired.

Gulf of Mexico.-From Key West to New Orleans there are several detached stretches of inside waters, available for a draft of 4 to 5 feet (1.2 to 1.5 m.), and a partially sheltered route with frequent harbors for small craft along the entire coast.

From New Orleans westward through Louisiana there is a network of inside waters affording a through route, for drafts of 3 to 5 feet (0.9 to 1.5 m.), to Sabine Pass. From Sabine Pass to Galveston there is no inside route.

From Galveston southwestward to Corpus Christi there is an inside route for a draft of 4 feet (1.2 m.) by way of several extensive bays and dredged canals connecting them. Beyond Corpus Christi there is no inside route available.

Charts covering the routes along the Atlantic coast and Gulf of Mexico are published by the United States Coast and Geodetic Survey.

A catalogue showing the charts of the route along the Atlantic and Gulf coasts can be obtained free of charge on application to the Coast and Geodetic Survey, Washington, D. C., or to any of its agents. A list of agents for the sale of charts and other publications of the Coast and Geodetic Survey is given in the catalogue and in the first notice each month of the Notice to Mariners, published weekly by the Bureau of Lighthouses and the Coast and Geodetic Survey.

The inland waters are covered in the following publications of the Coast and Geodetic Survey.

United States Coast Pilot, Section A, St. Croix River to Cape Cod.

United States Coast Pilot, Section B, covering the coast and inland waters from Cape Cod to Sandy Hook, including Long Island Sound, New York Harbor, and tributaries.

United States Coast Pilot, Section C (this volume), covering the coast and inland waters from Sandy Hook to Cape Henry, including Delaware and Chesapeake Bays, and the inside route from New York to Norfolk.

Inside Route Pilot, coast of New Jersey.

United States Coast Pilot, Section D, covering the coast from Cape Henry to Key West and inland waters from Cape Henry to Beaufort, N. C.

Inside Route Pilot, New York to Key West.

United States Coast Pilot, Gulf Coast, Key West to the Rio Grande. Inside Route Pilot, Key West to the Rio Grande.