Marks to Clear the Corsair Rock.

In working out between the Heads, keep the flagstaff on Observatory Point open half a cable’s length with the lowest part of Nepean Point until Shortland’s Bluff flagstaff is half a cable’s length open to the westward of the low lighthouse; which latter mark must be kept on until you open out Nepean Rock to the eastward of that point, when you are out clear of the rock and Nepean Reef.

In working in between the Heads, keep Shortland’s Bluff flagstaff half a cable’s length open to the westward of the low lighthouse until you have the flagstaff on Observatory Point half a cable’s length open to the lowest part of Point Nepean, which will lead you clear of the Corsair Rock; but to clear Nepean Reef, which lies a cable’s length inside the rock, do not shut in the low lighthouse with Shortland’s Bluff flagstaff until you open out the Nepean Rock to the westward of that point, when you are in clear of the reef.

NOTICE TO COMMANDERS OF VESSELS IN HOBSON’S BAY.

Commanders of vessels are requested to take notice that for the purpose of enabling them to rate their chronometers, a Time Ball, painted black, will be dropped daily (Sundays excepted), from the top of the flagstaff at Gellibrand’s Point, at the instant of 1 o’clock mean solar time, there corresponding to 15h. 20m. 19s. Greenwich time.

As a preparatory signal, a blue pennant will be hoisted at the mast-head at half-past twelve, and hauled down at ten minutes to one o’clock, when the Ball will be run up to the mast-head and dropped as above.

In the event of its being necessary at any time to suspend the dropping of the Time Ball either from strength of wind or any casualty occurring to the apparatus, this will be indicated by a white pennant being hoisted instead of the blue preparatory pennant.

Assigned position of the Time Ball, lat. 37d. 52m. 42s. S., long. 144d. 55m. 28s. E.

TIDAL SIGNALS.

A Flagstaff having been erected at Point Lonsdale, the following signals will be hoisted upon it between sunrise and sunset on and after this date, to denote the state of the tides at the heads:

A blue flag will be hoisted half-mast high when the tide begins to flow in the middle of the entrance between Points Lonsdale and Nepean, which will be kept flying all the first quarter of the flood tide.

The second quarter, a blue flag at the mast head.

The third quarter, a red flag half-mast high.

The last quarter, a red flag at the mast head.

Ebb Tides.

The first quarter, a blue flag, half-mast high, with a ball underneath.

The second quarter, a blue flag at the mast-head, with a ball underneath.

The third quarter, a red flag, half-mast high, with a ball underneath.

The last quarter, a red flag at the mast head, with a ball underneath.

River Yarra Yarra.

The following Tidal Signals will also be hoisted at the foremast head of the Water Police Hulk, moored at the entrance of the river Yarra, to denote the height of the tide on the bar:

When there is 8 feet water on the bar, a ball will be hoisted at the mast-head.

8½ feet ... a ball half-mast high.

9 feet ... two balls at the mast-head.

9½ feet ... two balls half-mast high.

10 feet ... a blue flag at the mast-head.

10½ feet ... a blue flag half-mast high.

11 feet ... a red flag at the mast-head.

CHARLES FERGUSON,
Port and Harbour Master.
December 22, 1853.