1028
THE HONGKONG GOVERNMENT GAZETTE, 19TH NOVEMBER, 1881.
South Banks, four in number, lie on the south side of the Middle channel; the north-westernmost bank, with 12 feet water, is 5 miles long in an east and west direction, and three quarters of a mile broad; its eastern end is in lat. 20° 11'50" N., long, 110° 52′ 20′′ E. the north-easternmost bank is 34 miles long N.E. by E. and S.W. by W., and half-a-mile broad, with 15 feet on its S.W. and 24 feet on its N.E. end, which is in lat. 20° 14′ 20′′ N., long. 110° 54′ 40′′ E. The south-easternmost bank, with 16 feet on it, is 2 miles long in an east and west direction, and half-a-mile broad; its eastern extreme is in lat. 20° 11′ 10′′ N., long. 110° 55' 40" E. The southernmost bank, situated S.W. 2 miles from the south-east bank, is 3 miles long, one mile broad, and has 18 feet on it at low water springs.
Little Bank, the east extreme of which lies N.W. by N. 3 miles from Haïnan bluff, is composed of sand 2 miles long and a quarter of a mile broad; the least water is 10 feet, with deep water close around.
Sheldrake Islet is a sand bank 7 feet high, 4 miles long, E.N.E. and W.S.W; and three quarters of a mile, broad; its eastern end which marks the entrance to Nowchow passage is in lat. 20° 23′ 10′′ N., long. 110° 37′ 10′′ E.
Overfalls.-Heavy overfalls or tide rips exist all over Haïnan strait, but especially between Hainan point and Little bank, and to the northward of Little bank.
There are also patches of discoloured water, which, however, are chiefly composed of minute algæ.
DIRECTIONS.-A vessel bound through Haïnan strait from the eastward can either proceed between the Haïnan banks by the North; or Middle channel; or, first make the Taya islands, and proceed through South channel and Inner passage round Mofou point and Haïnan head.
If taking either of the channels between the banks, a position by observation before nearing them is desirable, as they do not always break, and the soundings, being irregular, give but little notice of approach.
North Channel.--From a position in lat. 20° 29′ N., long. 111° 00' E., a S.W. I W. course leads through the North channel, (when Pochin pagoda is sighted it should be well open to the westward of Hainan bluff,) and when Haïnan bluff bears S. by W. W., a W. by S. S. course (allowing for tide) will lead north of Little bank to abreast Backsha point fishing stakes, when a course may be shaped for the anchorage in Hoi-How bay.
Middle Channel.-Being in lat.20° 19′ N., long. 111° 0' E., a W. by S. 4 S. course will lead 5 miles north of Haïnan bluff, passing clear of all banks, to abreast Backsha fishing stakes.
South Channel and Inner Passage.'-Having made North Taya island, a course should be shaped so as to pass Mofou point at about 2 miles distance, after which a W.N.W. course (allowing for tide) will lead towards Hainau head. When within 3 miles of Haïnan point, great caution is necessary to avoid the outlying rocks on the western, and the shoal water off the sand bank on the eastern side, which narrows the channel to half-a-mile. There is also a spit running out from the shore, with as little as 10 feet of water on it, the eastern extreme of which lies S.E. by E. 4 miles from Haïnan bluff.
When Hainan point extreme bears N.W. by W. W., the sand bank 3 feet high N.E. by E., and Pochin pagoda just. seen over the high sand hills (from a height of 18 feet), and bearing S.W, by W. W., a course of N.W. N. (allowing for strong tide) should be shaped so as to pass 2 or 3 cables from the outer rock (dries 4 feet) off Haïnan point.
After rounding this rock and when Pochin pagoda is again sighted clear of the rocks off Haïnan bluff bearing S.W., a W. S. course will lead south of Little bank to abreast Backsha point.
Caution is necessary should the flood stream be running not to be set towards Backsha spit.
Tides. It is high water, full and change, at Haïnan bluff, at 10 h. 35 m.; springs rise 6 feet, neaps 4 feet, neaps range 2 feet. There are two high and two low tides in the 24 hours which are regular at full and change, but not so at the first and last quarter. The flood stream runs generally for about 12 hours, as also does the ebb stream (there being hardly any slack water); the latter commences between the 5th and 6th hour after high water by the shore.
knots.
In the North channel the flood sets S.W. by W. from one to 3 knots an hour, and the ebb N.E. by E. from one to 31⁄2
In the Middle channel the flood sets N.N.W. from 1 to 3 knots, and the ebb N.E. by E. one to 3 knots. On the South banks the ebb sets E.S.E. one to 3 knots.
In the Inner passage the flood sets N.N.W. from one to 3 knots, and the ebb S.S.E. 14 to 3 knots, but at Haïnau point the tide is very strong (4 to 5 knots at springs) and irregular.
In the strait off Little bank the flood sets to the south-west 3 knots towards Pochin lagoon.
Winds.-Sharp squalls lasting from 10 to 20 minutes are common in Hainan strait during the months of June and July, often blowing with a force of 6 to 8; these squalls are generally preceded by a blue haze or tint over the land, and are very dangerous to boats under sail or with awnings spread.
The following is a table showing the average force and direction of the winds, from May to September, deduced from the observations of the Magpie.
Month.
Average Direction and Force of Wind.
May
June
From South to S.E. Force 1 to 4.
From South to S.E. Force 1 to 4.
July
August
September
From South to S.E. Force 1 to 4.
Occasionally North-easterly and calm, the latter part Westerly, 2 to 4.
From South to West. Force 1 to 4.
Occasionally S.E., 2 to 3.
Remarks.
A short rain-squall nearly every afternoon,
Rain-squalls as in May, a heavy gale from South on 28th June,
force 10, lasting for 12 hours.
Rain-squalls less frequent. 17th July, heavy gale from North for 12 hours, when it shifted to South and blew just as hard (9 to 10) for 12 hours.
A few rain-squalls. 1st August, heavy gale as on 17th July.
August 31st, typhoon for 24 hours, force 11 to 12. Barometer, 28.85 inches.
Variable, North-easterly to South- Hardly any rain-squalls.
easterly, Force 1 to 4.
Hydrographic Office, Admiralty, London, 25th August, 1881.
1 See Admiralty plan :-Inner passage, on chart of Haïnan strait, No. 876.
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