667576-1886-Hydrographic-Notices- — Page 2

THE HONGKONG GOVERNMENT GAZETTE, 26TH JUNE, 1886.

587

arks and suggestions, drawn up from a re-examination of the main channels connecting Cockburn Sound

completed during February and March, 1886, by Staff-Commanders Coghlan and Jarrad, R.N.

I have &c.,

J. E. COGHLAN, Staff Commander, R.N., in charge of Admiralty Survey.

tain M. S. SMITH,

&c.,

&c.,

&c.,

Acting Colonial Secretary,

main channels connecting Cockburn Sound with the ocean have been re-surveyed, to ascertain if the dep

(as reported) since the survey made by Staff-Commander Archdeacon, R.N., in 1872. Our re-exa ger Pass proves that the alleged increase of depth in that channel has not taken place. The princ Pass) communicates with the ocean about midway between Garden and Carnac Islands, and is barely ards) wide at its narrowest part, between Stag Rocks and Flat Ledge. The depths vary from 19 to 30 dent, pth being found on small rocky heads, which obstruct the channel, with from 27 to 36 feet close around them. natural leading marks to guide a vessel clear of these dangers. A current usually sets obliquely across the er to the N.E. or S.W., according to the direction of the wind; and, therefore, a sailing vessel cannot always feet rocks, and might be carried over them before the leadsman could call the soundings. A considerable s usually experienced in the channel, for which an allowance must be made of from 2 to 3 feet. Therefore, rest to His Excellency the Governor that the present regulations, which prohibit vessels of over 16 feet draught

through the Challenger Pass, could not be altered without danger to navigation.

se re-examination was also made of the channel nearest to Garden Island (called on the charts "North Channel"), y of ascertaining whether or not a better channel than the Challenger Pass existed in that locality, as from a of the published chart, appeared to be indicated. Our re-survey, however, led to the discovery of several inken dangers, with from 9 to 18 feet on them, and deep water close around; and clearly shows that vessels Attempt "North Channel" (unless compelled by circumstances to do so), but proceed by the Challenger Pass, at 18 feet is the greatest draught that can be taken through the latter channel in safety."

$ recently discovered in the "North Channel" are remarkable sandstone pinnacles, the sounding-lead summits suddenly into the deep water which surrounds them. Although the soundings give little or no the approach to these dangers, the bright yellow pinnacle rocks can readily be discerned from a boat during and a clear sky.

ended is a description of the principal dangers discovered, which His Excellency the Governor may deem of portance to local navigation as to necessitate a "Notice to Mariners". being published in the Gazette.

ì

X

J. E. COGHLAN, Staff-Commander, R.N.,

in charge of Admiralty Survey,

NOTICE TO MARINERS.

AUSTRALIA-WEST CO.........ï.

APPROACHES TO COCKBURN SOUND: NORTH CHANNEL, CHALLENGER PASS. owing information has been received from Staff-Commander J. E. COGHLAN, R.N., in charge of Admiralty estern Australia, the result of a recent examination of a portion of the approaches to Cockburn Soun

(All bearings are Magnetic. Variation 5° Westerly, in 1886.)

FATHOM BANK.-Hawley Shoal (on which the vessel of that name struck when crossing the Five- 3) has 16 feet on it and from 27 to 30 feet close around. From the centre of the shoal, Rottnest Island ars N.N.W., W.; Buckland Hill obelisk open of west extreme of Carnac Island, N.E.; Haycock Hill on d, East, distant 2 miles; and base of conspicuous sandpatch on Garden Island, S.E. § S.,

k, with 18 feet on it and from 26 to 30 feet close around, lies E. by S., distant 2 cables from Hawley Shoal. with 18 feet on it and from 28 to 30 feet close around, lies S.E., distant 3 cables from Hawley Shoal. ng mark.-The obelisk over Jervoise Bay in line with Entrance Rocks (north-west extreme of Garden Island)

N., leads over the Five-fathom Bank, between Casuarina and Hawley Shoals, in not less than 28 feet. H CHANNEL.-Jewfish Rock, with 9 feet on it and 24 feet close around, lies nearly in mid-channel th-West Spit and Sea Reef, with the following marks and bearings :-Rowboat Rock just open northward of bearing N. by E. † E.; sun. of conspicuous clump of trees north of Buckland Hill obelisk just open south N.E.N., conspicuous sandpatch on Garden Island in line with rocky point under laycock Hill, S. by E. ager Rock buoy in line with westernmost (smail) Straggler Rock, N. W.; and Inner Rock buoy open

Woodman Point Quarantine Station, E. N.

k, with 17 feet on it and from 22 to 26 feet close around, lies S.E., distant 1 cable, from Jewfish Rock.

Rock, the shoalest head of a cluster of pinnacles, has 10 feet on it and 34 feet close around, with the arks and bearings :-Rowboat Rock, in line with western extreme of Carnac Island, N. by E. E.; and obelisk

Bay, in line with northern of two conspicuous clumps of trees, E. 3.

Stones Rocks are a cluster of seven pinnacles, with from 7 to 12 feet over them, and 2 to 40 feet d them. The southernmost pinnacle, with 12 feet on it, lies N.N.W. W., distant 3 cables, from the northern Surface Reef.

ate Rock, with 17 feet on it and from 26 to 28 feet close around, lies S. § W., distant 11⁄2 cable, from the

on (16 feet) of the Three-fathom Bank.

ok, with 14 feet on it and from 31 to 38 feet close around, lies S.E. E., distant 1 cable, from Bishop Rock. ak with 9 feet on it and 24 feet close around, lies N.W., distant 1 cable, from the northern extreme of Sur-