Sailing Directions For The Navigation About Rottnest Island

Rottnest Island, 6 miles in length E. by N. and W. by S. with an extreme breadth of 2½ miles, has an irregular hummocky surface, not much wooded, and may now be distinguished from Garden Island and the contiguous main land by a white obelisk, 15ft. in height, with a pole in the middle, of the same length, which has recently been erected on its highest part near the centre of the Island. This sea-mark, being elevated about 157ft. above the level of the sea, may be seen from a ship's deck in clear weather at the distance of 7 or 8 leagues, and will shortly give place to a lighthouse of greater elevation. Its position, according to observations in H.M.S. Beagle, is lat. 32d. 0m. 14s. South, long. 115d. 29m. 6s. East from Greenwich.

To round the Island on its north side, a ship should not approach nearer than one mile, in order to avoid the Horseshoe Rock which lies ¾ of a mile off shore, at the distance of two miles N. 396. E. from the Island's west extremity, and Roe's Reef situate ¾ of a mile N. 16 deg. W. from a small rock with a cask beacon upon it, about half a cable's length from the island's N.E. point. The beacon is upon Duck Rock, and the projection near it is Bathurst Point. A ship will be clear to the northward of Horse-shoe Rock while Duck Rock beacon is kept open of the N. point of Rottnest; and Roe's Reef may be cleared on the north by keeping the west end of Rottnest (Cape Vlaming) open of the north point, until Duck Rock bears south; a course may then be shaped about E. by S. for a remarkable white sand patch on the main, which will be distinctly visible 3½ miles north from the entrance to Swan river; and when some rocky islets near the S.E. side of Rottnest are seen to the SSW., opening near the east end of another small rock with a cask[?] beacon upon it 1¼ mile SE½E from Duck Rock, a SE by E course will conduct in Gage's Roads.

Kingston Spit, in front of Thompson's Bay, extends 2 miles east from Duck Rock, and a long mile NE by E from the beacon last mentioned, which has recently been placed upon Fisherman's Rock, a small mass of white rocks about 2 cables length NE from the sandy east point of Rottnest Island, distinguished by the name of Point Philip. To clear Kingston Spit on the north, keep Duck Rock a little shut in to the south of a bare pointed hill near the northern shore of Rottnest; or should the bare hill not be distinguished, keep the north extreme of Rottnest to the southward of W½S; and to clear Kingston Spit on the south, keep the south extreme of Rottnest (Point Parker) open of the next projection to the N.E. of it (S.W. by W.)

Thompson's Bay is a fit resort for boats only, being full of shoal rocky patches and sand banks, to the distance of a mile from the shore,—the remainder of Kingston Spit being occupied by foul uneven ground, with depths varying between 5 and 2 fathoms; near its north and east edges are 7 fathoms, deepening to 9 and 10 in ½ a mile. Between Point Philip and the next projection along ½ mile to the SSW (Bickley Point) there is good shelter in Beagle's Anchorage from all the usual NW and SW gales of winter, the best birth being in 4 fathoms water, sandy ground, nearly ½ a mile south from Fisherman's Rock, and a ¼ of a mile NE from two small rocks called the Twins,—the south point of Rottnest being also in a line with Bickley Point. In this situation a vessel should moor, on account of the limited space.

On the SE side of Rottnest there is a good channel, 2½ miles wide, called the Southern Passage into Gage's Road,—the only obstruction in it being a patch of 3 fathoms, sand and weeds, called Middle Bank, in a line between Point Philip and the Champion Rock, at 1¾ miles from the former, and 1¼ miles from the latter. After a gale; the NW swell round the east end of Rottnest crossing the ocean roll from the S W, breaks heavily at this spot, and indicates its position; it may, however, be avoided by borrowing towards tho rocky islets near Rottnest, which have no dangers fronting them beyond a cable's length; and the bank is cleared to the eastward when the beacon on Duck Rock opens round to the NE'd of that on Fisherman's Rock. These 2 beacons in a line lead also about a cable's length to the NE of the Champion Rock, which has only 9ft. water upon it, with 4 & 5 fathoms all around. This danger, which lies on the SE side of the Southern Passage, is at the NW extremity of a collection of rocks and foul ground that extend 2½ miles NNW ½ W from the Stragglers toward the east end of Rottnest, without any channel amongst them which can yet be pronounced safe. In working up for the southern passage with a northerly wind, the Champion Rock and dangers in its vicinity may be avoided by keeping the high lump of rock called the Mewstone, open to the SW of the largest and highest of the Stragglers, until the SW end of Rottnest shuts in round its south point, bearing about W½N. This last mark will carry a ship clear between Champion Rock and Middle Bank; but should the Mewstone and Stragglers not be satisfactorily distinguished, the beacon on Fisherman's Rock should not be brought to bear more to the westward than N 30d. W by compass, until the SW point is shut in by the south point of Rottnest, as before shewn.

Approaching Rottnest and Southern Passage.: In steering for Rottnest Island and the southern passage from the westward, the shore should not be approached nearer than half a mile, and the bays on each side of the south point are foul and rocky. Porpoise Bay, on its NE side, is also fronted by a low rocky mass called Direction Islet, which lies 1¼ miles E 23d. N from the south point, and has deep water to within a cable's length of its SE side. The summit of Direction Islet in a line with a hill with some trees on its summit (Tree Hill), about ½ a mile to the north of the south point, leads directly over Middle Bank; therefore Tree Hill a little open to the north of Direction Islet leads clear to the north of Middle Bank,—and the same hill on with south point of Direction Islet leads clear on its south side. The next grey rock (Wallace islet) ½ a mile to the NNE, is very rugged, and lies close in to Bickley Point,—it has 2½ fathoms, rocky ground, nearly ¼ of a mile SE of it, which may be avoided in hauling up for Beagle's Anchorage by keeping the south point on with the southern extreme of Direction islet until Fisherman's Rock bears North. The Twin Rocks lie near each other, ¼ of a mile NE from Wallace Islet, and are bold and steep. Round their NE side is Beagle's Anchorage, which is a secure retreat in winter.

Currents.: In beating up to Rottnest against a strong northerly or southerly breeze, much ground will be gained by working in the stream of the island, in order to avoid the strength of a lee current which is found on such occasions to run at the rate of 1 to 1½ miles an hour. The Beagle found it highwater at full and change in Thompson's Bay at 7h. 50m. ,—tide ebbing 10 hours, and flowing 14 hours, with a rise not exceeding 32 inches.

Winds.:—Sea and land breezes prevail in summer. From March to October, NW gales may be expected, rising from the north ward, preceded by a fall in the barometer,—blowing longest at NW,—strongest between WNW and W,—and moderating after a hard squall from the S.W.

J. S. ROE,

Surveyor-General.

Western Australia, Oct. 15, 1840