The flood current sets NE directly through the passage, and the ebb in the opposite direction, at rates of 5 to 6 knots at springs.
In the narrowest part, abreast of Lumpai the eddies make steering difficult.
Depths from 33 to 59m were reported to lie about 3 miles N of Ujung Bau.
Aroih Cut (Aroih Tjoet) may be used by small vessels with a speed of not less than 8 knots.
A vessel approaching from S should steer for Ujung Raya, which is difficult to identify from a distance.
After rounding this point steer for the NE entrance of the strait. A good speed must be maintained when passing through this narrow passage.
A vessel bound W through Aroih Cut (Aroih Tjoet) should steer for the summit of Pulau Bunta, bearing about 247°, passing midway between Ujung Masammuka and Lumpai, then closing the SE shore of the passage, especially during the W currents.