Currents. The time of slack water, the duration of flood and ebb, and velocity of the current are greatly affected by freshet conditions in the river. The time of the strength of the current is not greatly affected by freshet conditions and occurs as follows: Fort Washington, about 214 hours after the corresponding strength at the Narrows (approximately 12 hour after high and low water at the Battery); Dobbs Ferry, about 234 hours after strength at the Narrows (approximately 114 hours after high and low water at the Battery); Croton Point, about 34 hours after strength at the Narrows (approximately 2 hours after high and low water at the Battery); Donderberg, about 31⁄2 hours after strength at the Narrows (approximately 2 hours after high and low water at the Battery); West Point, about 4 hours after strength at the Narrows (approximately 22 hours after high and low water at the Battery); Poughkeepsie about 434 hours after strength at the Narrows (approximately 314 hours after high and low water at the Battery).

The observed velocities of the currents range from 1 to 3 knots from the Battery to Dobbs Ferry, and the mean velocity is about 2 knots. Above Dobbs Ferry the ordinary velocity ranges from about 1 to 12 knots, the ebb having slightly the greater velocity. Between Barrytown and New Baltimore the average strength of current at low stages of the river is from 12 to 2 knots, at Castleton about 1 knot and at Albany about 1⁄2 knot. At Troy the current ebbs continually. See also the statement relating to freshets following.

Freshets. During March, April, and May freshets may be expected of from 8 feet upward in height at Albany above the plane of lowest low water and lasting through periods of 10 days and more. During warm months freshets may be expected from 8 to 14 feet in height at Albany above the plane of lowest low water, with from 3 to 5 days' duration. Rain freshets are not, as a rule, very destructive, the main damage being interference with navigation due to wharves being under water. Freshets caused by ice gorges, which occur nearly every year in February or March, usually rise higher, last longer, cause loss and destruction on shore, and form shoals and bars in the channel.

During low-water stages at Albany there is an ebb current for about 7 hours and a clearly definable flood current for from 211⁄2 to 4 hours. When the freshet low water rises to mean half tide the flood current disappears, and the tidal wave is felt only by small fluctuations in the water level. When the freshet height reaches 10 feet above the plane of lowest low water the tidal action ceases to be apparent. During low stages at Albany the velocity of the flood current at strength is about 1/4 knot and the ebb 34 knot. During freshets of not less than 6 feet the flood current disappears and there

is an ebb current of about 12 knots. After the flood current disappears the average difference in the velocities of the ebb current between flood and ebb tides is about 114 knots, and during extreme freshets the current reaches a velocity of nearly 5 knots.

Ice closes navigation on the upper Hudson River from about December 12 to March 24. In recent years the dates of opening navigation ranged from March 14 to April 4, and of closing navigation ranged from December 1 to January 3. In 1931, however, navigation remained open all year. Canal navigation usually closes about December 10.

Hospital.-There is a relief station of the United States Public Health Service at Albany.

BRIDGE REGULATIONS

The following are the regulations prescribed by the Secretary of War to govern the opening of the drawbridges crossing the Hudson River at Albany:

1. The draw in each of the bridges crossing the Hudson River at Albany, N. Y., shall, upon the signal prescribed in paragraph 9 below being given, be opened promptly at all hours for the passage of any vessel or vessels or other water craft not able to pass underneath it.

2. The draw of a bridge shall not be required to remain open for the passage of vessels longer than 15 minutes consecutively, and upon being closed it shall be authorized to remain closed for a sufficient time to allow delayed land traffic to pass over, and in no case exceeding the period of 10 minutes consecutively, unless at the expiration of such a period a train in motion having passed the derailing point is approaching the draw, which train shall be permitted to pass the draw before opening: Provided, That no train shall be stopped on the bridge between the derailing points except in a case of great emergency, after which it shall be opened promptly for any vessels desiring to pass the draw: Provided, That this regulation shall not apply to any vessels of more than 500 tons burden, to a tug with a tow on a hawser, or to single tows which require longer than 15 minutes to pass through the draw, or to any vessels down bound during the freshets whose height exceeds 51⁄2 feet above the plane of lowest low water, as determined by the War Department.

3. The length of time that a draw has been open shall be computed from the time that the draw span begins to move in opening, and the length of time that a draw has been closed shall be computed from the time that the draw span ceases to move in closing.

4. Vessels with tows shall not so approach a bridge as to attempt to pass the draw in succession without interval. They must arrange their approach so as to cause no delay in closing the draw promptly for the relief of land traffic.

5. The draw of a bridge shall not be required to be opened to permit the passage of vessels habitually using said river, which have stacks, jack staffs, or flagstaffs exceeding 21 feet in height above the water line, and which are otherwise capable of clearing the bridge when closed. If such vessels wish to pass the bridge, the stacks, jack staffs, or flagstaffs must be so erected that they may be lowered to permit the passage under the bridge.

6. Any tug or vessel passing the draw of a bridge at Albany as often as once a day for 10 consecutive days of any month will be regarded as using the river habitually in the meaning of paragraph 5 of these regulations. A failure to comply with that regulation by any tug or vessel after one warning by the persons owning or controlling any of the Albany bridges shall be sufficient cause for refusal to open the draw for the accommodation of said tug or vessel until such later time as may be convenient to the persons controlling the bridge.

7. These regulations shall not apply to vessels which are owned or controlled by the United States Government or by the police or fire departments of the cities of Albany, Rensselaer, Troy, and Watervliet; such vessels shall be passed without delay through the draws of the bridges on identification.

8. Signals. The signal for boats desiring to use the draw shall be by whistle or horn, as prescribed in paragraph 9. The signals from the bridges shall be by blasts of whistle or horn with an additional visible signal as prescribed below. A long blast of whistle or horn shall continue 5 seconds, a short blast 1 second.

The visible signals, by day, shall be displayed at least 15 feet above the fixed day signal at the middle point of the draw span and visible from both sides of the bridge, and by night at a height of at least 15 feet above the fixed light at the center of the draw, the "fixed" signals referred to being those required by the general regulation for lighting bridges over navigable waters." By day, if the draw is to be opened, the visible signal shall be a round ball not less than 3 feet in diameter and painted green, or, if the draw is not to be opened, it shall be a latticework barrel-shaped sign 5 feet 6 inches high and 4 feet in diameter painted red.

By night, if the draw is to be opened, the visible signal shall be a green light from a standard marine lamp, or, if the draw is not to be opened, it shall be a red light from a standard marine lamp.

9. Signal code, vessels bound north.-A vessel bound north shall, on approaching a bridge, give three long blasts of the whistle or horn.

Vessels bound south.-A vessel bound south shall, on approaching a bridge, give three long blasts followed by one short blast of the whistle or horn. If a vessel desires to pass through more than one bridge the signal calling for the bridge to be opened will be repeated for each bridge.

If a draw is to be opened, the signal from the vessel shall be answered from the bridge by three long whistle blasts and by displaying the green-ball visible signal. If the draw is not to be opened in time for the vessel to pass through safely, five short blasts of the whistle shall be sounded and the red-barrel visible signal be displayed.

10. Private signals of towing or steamboat companies should not be used if in any way they may be mistaken by the bridge tender for signals of the regular code.

The following are the regulations prescribed by the Secretary of War to govern the opening of the drawbridges crossing the Hudson River at Troy:

1. The draw in each of the bridges crossing the Hudson River at Troy, N. Y., below the head of tidewater shall, upon the signal prescribed in paragraph 9 below being given, be opened promptly at all hours for the passage of any vessel or vessels or other water craft not able to pass underneath it, except that the bridge of the D. & H. Co. need not be opened between the hours of 6 p. m. and 6 a. m., unless notice has been given before 6 p. m. of the time or times when vessels may be expected to pass through.

2. The draw of a bridge shall not be required to remain open for passage of vessels for a period longer, consecutively, than 15 minutes. Upon being closed it may remain closed for a time sufficient to allow delayed land traffic to pass, but in no case exceeding a period of 10 minutes, consecutively, if a vessel desires to pass the draw: Provided, That these limitations shall not apply to vessels of more than 500 tons burden, to a tug or tugs with a tow on a hawser, or to any vessels down bound during freshets, when the freshet height exceeds 51⁄2 feet above the plane of mean high tide, as determined by the War Department.

3. The length of time that a draw has been open shall be computed from the time that the draw span begins to move in opening, and the length of time that a draw has been closed shall be computed from the time the draw span ceases to move in closing.

4. Vessels with tows shall not so approach a bridge as to attempt to pass the draw in succession without interval. They must arrange their approach so as to cause no delay in closing the draw promptly for the relief of land traffic.

5. The draw of a bridge shall not be required to be opened to permit the passage of vessels habitually using said river, which have stacks, jack staffs, or flagstaffs exceeding 21 feet in height above the water line, and which are otherwise capable of clearing the bridge when closed. If such vessels wish to pass the bridge, the stacks, jack staffs, or flagstaffs must be so erected that they may be lowered to permit the passage under the bridge.

BRIDGE REGULATIONS

331

6. Any tug or vessel passing the draw of a bridge at Troy as often as once a day for 10 consecutive days of any month will be regarded as using the river habitually in the meaning of paragraph 5 of these regulations. A failure to comply with that regulation by any tug or vessel after one warning by the persons owning or controlling any of the Troy bridges, shall be sufficient cause for a refusal to open the draw for the accomodation of said tug or vessel until such later time as may be convenient to the persons controlling the bridge.

7. These regulations shall not apply to vessels which are owned or controlled by the United States Government or by the police or fire departments of the neighboring cities or villages; such vessels shall be passed without delay through the draws of the bridges on identification.

8. Signals.-The signals for boats desiring to use a draw shall be by whistle or horn, as prescribed in paragraph 9. The signals from the bridges shall be by blasts of whistle or horn.

9. Signal code, vessels bound north.-A vessel bound north shall on approaching a bridge give three long blasts of the whistle or horn.

Vessels bound south.-A vessel bound south shall on approaching a bridge give three long blasts followed by one short blast of the whistle or horn.

If a vessel desires to pass through more than one bridge, the signal calling for the bridge to be opened will be repeated for each bridge.

If a draw is to be opened, the signal from the vessel shall be answered from the bridge by three long blasts of whistle or horn. If the draw is not to be opened in time for vessel to pass through safely, five short blasts of the whistle or horn shall be sounded.

10. Private signals of towing or steamboat companies should not be used if in any way they may be mistaken by the bridge tender for signals of the regular code.

DIRECTIONS, HUDSON RIVER

For the charts covering Hudson River see the index map facing page 1.

The channel of Hudson River is broad and has few obstructions as far as Roundout. It is good for a depth of 27 feet (8.2 m) to Albany and 12 feet (3.7 m) to Troy.

From the Battery to Irvington, about 22 miles, the deepest water follows the east bank and then leads between the shoals along the east bank and the extensive shoals, fringed by broken ground, making off from the west bank from southward of Piermont to Rockland Lake Lighthouse.

Broken ground, on which the least depths found are 13 to 21 feet (4 to 6.4 m) extends in a northerly direction across the channel and lies from 2 to 3 miles northward of Tarrytown Lighthouse. Three lighted buoys, lying 134, 3, and 4 miles, respectively, northward of Tarrytown Lighthouse, mark the east edge of the channel abreast the broken ground and assist in avoiding it, but strangers should proceed with caution in vessels drawing more than about 15 feet (4.6 m).

About 6 miles above Tarrytown and 5% mile westward of the south end of Croton Point is a shoal spot with 18 feet (5.5 m) over it, which is marked by a horizontally striped buoy.

A shoal bank, with a least depth of about 23 feet (7 m), extends southward from the Donderberg, opposite Peekskill, and lies on the west side of the channel.

With the exception of the flats in the bights and along the banks, the obstructions in the channel above the Donderberg are rocky.

A rock with 9 feet (2.7 m) over it lies on the west side of the channel 400 yards from the west bank and 350 yards north-north

161875°-33-22

westward of the north end of Iona Island. This rock is marked by a horizontally striped can buoy.

Con Hook Rocks, with 8 feet (2.4 m) over them, lie 300 yards from the west bank and nearly 3 mile south-southwestward of the light at Con Hook; the rocks are marked by a black lighted buoy.

The Brothers is a ledge, partly bare at extreme low water, which lies on the east side of the channel off the shoal bight northward of Constitution Island, and is marked by a red buoy.

Diamond Reef has 5 feet (1.5 m) over it, and lies near mid-river off the lower end of New Hamburg. It is about 300 feet in diameter, with depths of less than 18 feet (5.5 m), and is marked near its shoalest part by a horizontally striped lighted buoy. The gas buoy is withdrawn from station between December 1 and April 1; spar buoy on station throughout year. There is a clear channel on either side of the reef.

A rocky patch with a least depth of 18 feet (5.5 m) lies 300 yards from the east bank off a sand wharf which lies about 31⁄2 miles northward of New Hamburg. The rock is marked by a horizontally striped buoy.

Another small rocky patch with 18 feet (5.5 m) over it lies in from the east bank off a sand wharf which lies about 32 miles northkeepsie and is marked by a horizontally striped buoy.

From Rondout to Hudson the channel has a navigable depth of 27 feet (8.2 m), but is rendered more difficult than southward of Rondout by reason of numerous middle grounds and flats. With the aid of the chart, however, small vessels should have no difficulty in making the passage. From Kingston Point to Barrytown the channels on both sides of the Flats are used. The principal channel then leads westward of the Hogs Back, eastward of Saddle Bags, westward of Green and Upper Flats, westward of Upper Coal Beds (there is 24 feet (7.3 m) on the east side), westward of Rogers Island and eastward of Middle Ground Flats to Hudson.

From Hudson to Troy the river is being improved to obtain a channel 300 feet wide, with 400 feet through the rock cuts, to the Albany-Greenbush bridge in Albany, thence 400 feet wide to Troy. The depth to Albany is 27 feet (8.2 m) and 12 feet (3.7 m) to Troy, but not for the full width of the project. The channel is well marked by buoys and lights. The bottom is rocky at many of the bars under improvement, and some local knowledge is required to insure safety for anything but small craft. Strangers are advised to take a pilot; one can be obtained at Hudson and at other cities and towns on the river, but pilots are usually engaged at New York.

INLAND WATERWAYS

New York State Canal System.-The New York State Barge Canal, known as the Erie Canal, affords an all-water route from the Hudson River on the east to Lake Erie. The canal is free for the use of both commercial and pleasure vessels. The canal was constructed for a depth of 12 feet throughout, but in 1930 the controlling depth was about 10 feet. Barges loaded to about 912 feet use the canal regularly.