The shelter for ships which may be caught so suddenly as not to be able to clear the land, are these: Two-fold Bay, for vessels of four-hundred tons and under; Jervis and Botany Bays, Port Jackson, and Broken Bay; Port Hunter for brigs and small craft; Port Stephens; Shoal Bay for vessels not exceeding fifty tons; Glass-house Bay; and lastly Hervey's Bay, by going round Break-sea Spit. All these places will be found in Plates VI, VIII, IX, and X. of the Atlas, with particular plans of the entrances to some of them. Directions for Port Jackson, and Botany and Broken Bays are given by captain Hunter in his voyage; and they may be found in Horsburgh's East-India Directory, Part II, p. 465-468. Two-fold Bay is described in the Introduction to this voyage, and mention made of Jervis, Shoal, Glass-house, and Hervey's Bays.
A ship sailing along this coast to the southward, should not, to have the advantage of the current, come nearer than five or six leagues unless to the projecting points; and if the distance were doubled, so as to have the land just in sight, an advantage would be found in it; and such an offing obviates the danger of the gales.
Whilst western winds prevail on the southern parts of the East Coast, the south-east trade blows with most regularity within, and close to the tropic, producing sea and land breezes near the shore, and serenity in the atmosphere; and the further we go northward the longer does this fine weather last, till, near Cape York, it commences with the month of April, probably even March, and extends to the middle or end of November. How the winds blow from November to April, I have no experience; but there is great reason to believe that they come from the northward, and make the wet season here, whilst dry weather prevails beyond the tropic. In Broad Sound and Shoal-water Bay we had more northern winds than any other, in the month of September; but these appeared to be altogether local, caused by the peculiar formation of the coast; for they did not bring any rain, though it was evidently near the end of the dry season, and we found the south-east trade wind before losing sight of the land.
[NORTH COAST. WINDS AND CURRENTS.]
The North Coast appears to have the same winds, with a little exception, as the tropical part of the East Coast. From March or April to November, the south-east trade prevails; often veering, however, to east, and even north-east, and producing fine weather, with sea and land breezes near the shore. At the head of the Gulph of Carpentaria, the north-west monsoon began to blow at the end of November; but further westward, at the northern Van Diemen's Land, I apprehend it will set in at the beginning of that month, and continue till near the end of March. This is the season of heavy rains, thunder, and lightning, and should seem, from our experience, to be the sickly time of the year.
It is thought to be a general rule, that a monsoon blowing directly in from the sea, produces rain, and from off the land, fine weather, with sea and land breezes; this I found exemplified on the west side of the Gulph of Carpentaria, where the rainy north-west monsoon, which then came off the land, brought fine weather: the rain came with eastern winds, which set in occasionally and blew strong for two or three days together. It seems even possible, that what may be the dry season on the North Coast in general, may be the most rainy on the west side of the Gulph; but of this I have doubts.
According to Dampier, the winds and seasons on the north-west coast of Terra Australis are nearly the same as above mentioned upon the North Coast; but he found the sea and land breezes, during the south-east monsoon, to blow with much greater strength.
In speaking of the currents, I return to the tropical part of the East Coast. Within the Barrier Reefs, it is not the current, for there is almost none, but the tides which demand attention; and these, so far as they came under my observation, have been already described, and are marked on the charts. At a distance from the barrier there is a current of some strength, at least during the prevalence of south-east winds; but instead of setting southward, as I have described it to do from Sandy Cape to Cape Howe, the current follows the direction of the trade wind, and sets to the north-west, with some variation on either side, at the rate of half a mile, and from thence to one mile an hour. This I found to continue amongst the reefs of Torres' Strait, nearly as far as Murray's Islands; but from thence onward through the strait, its direction in October was nearly west, something more than half a mile; and so continued across the Gulph of Carpentaria to Cape Arnhem, with a little inclination toward the south.
Along the north coast of Terra Australis, the current seems to run as the wind blows. In March, before the south-east monsoon was regularly set in, I found no determinate current until the end of the month, when Timor was in sight, and it then set westward, three quarters of a mile an hour; but in the November following, I carried it all the way from Cape Arnhem, as captain Bligh had done from Torres' Strait in September 1792; the rate being from half a mile to one mile and a quarter in the hour.
The navigation along the tropical part of the East Coast, within the Barrier Reefs, is not likely to be soon followed, any more than that round the shores of the Gulph of Carpentaria; nor does much remain to be said upon them, beyond what will be found in this Book II, and in the charts; and in speaking of the outer navigation, my remarks will be more perspicuous and useful if I accompany a ship from Port Jackson, through Torres' Strait; pointing out the courses to be steered, and the precautions to be taken for avoiding the dangers. It is supposed that the ship has a time keeper, whose rate of going and error from mean Greenwich time have been found at Sydney Cove, taking its longitude at 151° 11' 49" east; and that the commander is not one who feels alarm at the mere sight of breakers: without a time keeper I scarcely dare recommend a ship to go through Torres' Strait; and from timidity in the commander, perhaps more danger is to be anticipated than from rashness. The best season for sailing is June or July; and it must not be earlier than March, nor later than the end of September.