Between Pulau Turus and Batu Lanjang to the W, and Pulau Kundur to the E, there is a drying shoal. It extends about 3 miles NW from a position about 2 miles E of Batu Lanjang.
Two drying rocks, and a scrub covered rocky islet, lie about l.5, 2, and 3 miles SE of Batu Lanjang.
A clear passage, with a least depth of 5.8m in mid-channel, lies between these dangers and the NE side of Pulau Mendol.
In the strait between as well as outside these islands the flood sets to the SE, and the ebb to the NW; the ebb current being the stronger.