651652-1892-Hydrographic-Remarks — Page 1

THE HONGKONG GOVERNMENT GAZETTE, 17TH DECEMBER, 1892.

GOVERNMENT NOTIFICATION.-No. 525.

1099

The following is published.

By Command,

G. T. M. O'BRIEN, Colonial Secretary.

Colonial Secretary's Office, Hongkong, 17th December, 1892.

HYDROGRAPHIC REMARKS.

H. M. S. Penguin.

Affecting Charts Nos. 1199, 1429 and 1770. Bearings given are magnetic.

Soundings reduced to low water spring tide.

Nu pi shan channel is the name given to the inshore winter route between the Kweshan islands and Footo channels and is enclosed on the east side by the west coast of Luh wang, the Mesan group, Mouse island and Holdernesse rocks: on the west side by Nu pi shan, the Corkers, Wheps and Pylades rock. It is 20 miles long; and, in its narrowest part, 3 miles broad, the depth throughout being from 3 to 6 fms. In the fairway, lies Starboard Jack, which is generally left on the starboard hand when heading up to the northward; but there is a safe passage between it and Tinker with depth of 6 fathoms, mud bottom.

In the winter months when the prevailing winds are from the north this channel will be found useful for vessels of 18 ft. draught.

Tides. It is H. W. F. & C. at the Kweshan islands at 8 h. 33 m. springs rise 13ft. 6in. The tidal streams are rotary; and, so far as the conformation of the land will allow, run thus-with a speed of one to three knots per hour according to the age of the moon :-the first half of the flood between south and west; the last between west and north.

The first half of the ebb between north and east: the last between east and south.

Vessels wishing to make the most of the tidal stream, to approach the Yangtse, will pass Kweshan islands 2 hours after low water, and reach Footo two hours before high water by the shore. They will then have a swift tide through the Blackwall pass; and reach a position west of West Volcano island before the ebb stream has begun to make. The ebb stream will assist them slightly in their passage between West Volcano and Gutzlaff. The principal danger on the route is Hoar rock off the Rugged islands. Care must be taken not to bring S. W. Horn to bear west of south until Gutzlaff island is seen open to the west of Hen and Chicks or supposing Gutzlaff to be not visible- until Hen and Chicks bear N.E. by E. Rule for determining the time of the most favourable stream.-Add 7 hours to the time of the moon's meridian passage as given in the Nautical Almanack for Greenwich; and the result will be the mean time at which a vessel should be abreast of Footo in order to make the most of the flood stream.

The same rule holds good for determining the time at which a vessel should be at the mouth of the Vernon pass. The Vernon pass is easily found by a bearing of Taou Hwa summit, which is by far the highest mountain for many miles around.

Footo channels.-The best is the Gough pass as it is free from dangers; it is steep to on both sides; and a straight course can be preserved throughout.

Duffield reef.-The outermost rock is 6 cables from Clarence point; and it dries 4 feet at low water. highest Duffield rock, which is rugged and steep to and 53 feet high, bears N.E., distant 13 cables.

From it, the within 2 cables of the outer rock.

There is 46 fathoms

•

Tides.-At Roundabout island it is H. W. F. & C. at 10h. 2m. springs rise 13ft. 2in.

At Footo H. W. F. & C. about 9h. 45m. springs rise 13 feet. The stream is slack when it is half tide by the shore. The flood stream runs to the N.E. about 3 hours after low water: the ebb to the south and west 3 hours after high water by the shore; the speed being to 5 knots per hour according to the age of the moon.

The passage between Roundabout and the main is free from dangers; but the tide ripplings are severe.

In Tower Hill channel, the flood stream commences to run to the northwest 3 hours after low water; the ebb to the southeast 3 hours after high water: the speed being 3 to 7 knots according to the age of the moon. severe, especially during gales.

Tide ripplings anře

Combe rock is a dangerous pinnacle with 3 feet water over it, nearly two cables distant from Cliff island off Meishan. From it, the highest Central island appears just open of the left extreme of Robert island: and the summit of Cliff island bears N.W., distant 2 cables.

The mud bank northeast of Meishan has extended since the last Admiralty survey.

There is now only 17 feet as much

as 23 miles from the shore, the bank sloping up gradually to the northeast point of the island.

Roberts pass is narrow and its appearance is deceptive. It should not be used. Tygosan.-The mud bank off the western coast has extended since the last Admiralty survey; and is now as much as 7 cables from the shore.

The whole of the islet off Insular point open of the left extreme of Tygosan clears the bank.

Middle ground west of Kintang. The tail of this bank is situated 24 miles northeast from Tsele. line with Tiger island lighthouse leads over it in 14 feet sand.

Tsele lighthouse in

Directions.Vessels drawing over 15 feet approaching the Yung river from the north, should keep about half a mile from the projecting points at the western side of Taping, Taoutse and Kintang islands, and not port for the Yu islands until the Joss houses on the summit of Citadel hill are seen in line with the left extreme of Yu islands, when a more westerly course may be adopted. It is not safe to approach Tsele within one mile on account of the Penguin bank which has 17 feet over it; and from which Tsele lighthouse bears N. 25° W. 54 cables and Nemesis rock beacon in line with Look-out bill bears S. 39° W., distant one mile. Before Nemesis rock is brought within a distance of one mile, Tiger island lighthouse must be brought open to the left of the Yu islands. Pass the south extreme of Tayusan at a distance of half a cable on the starboard hand; pass Sesostris rock buoy 50 yards distant on the port hand; and steer for the 3 tier fort at the north extreme of Chung point, taking care that the right or south extreme of Tayusan is kept just open to the left of Sesostris rock buoy. When Tsele lighthouse is hidden behind Tiger island, starboard to pass Chung point half a cable distant on the starboard hand. Having passed Chung point and got it on the starboard quarter, starboard again for mid channel: shave the fishing stakes as close as possible on the port side and proceed up the river, or anchor off Chinhai as convenient.