The North Head bears from the Inner South Head North 53 degrees East by compass, about two thousand four hundred and forty yards; and the narrowest part of the entrance, which is between the Inner North and South Heads, is a little more than eight hundred yards, so that there is abundance of room to work in should the wind blow out of the Port.

On arriving off the lighthouse, steer in between the North and South Heads until you are past the line of bearing of the Outer North, and the Inner South Heads: then haul round the latter, but avoid a reef of rocks that extends for two hundred yards off the point, and steer for Middle Head, a projecting cliff at the bottom of the bay, until the harbour opens round the Inner South Head; you may then pass on either side of the Sow and Pigs; but the eastern channel, although the narrowest, is perhaps the best; but this, in a great measure, depends upon the direction of the wind.

The eastern channel is the deepest.

The Sow and Pigs, or Middle Ground, is the only danger in Port Jackson: it is a bank of sand and rocks, of about eight hundred yards in length, by about three hundred and fifty in breadth: its length being in the direction of the harbour; a very small portion of it is dry, and consists of a few rocks, upon which the sea almost always breaks; they are situated upon the outer end of the shoal, and are in the line of bearing of the Outer North and the Inner South Heads.

The south-western tail of the bank is chiefly of sand, with rocks scattered about it; but, on the greater portion of it, there is twelve feet water; it gradually deepens to three and a quarter fathoms, which is beyond the rocky limits of the shoal.