Between and in the vicinity of the islands are numerous reefs, for which the chart should be consulted. The 20m curve must be considered the limit of safety at Pulau Hinako, as nearly everywhere within this curve are drying reefs or reefs with little depth.
The W side of the four outer islands, with exception of the coast reefs on which there are usually breakers, is clear. By passing the islands at a distance of 1 mile, one will always carry considerable depths.
Hinako Islands: Asu and Bawa are two breaks in this island chain.
Pulau Bawa is atoll-shaped. The seaward side of all of the islands consists of a raw coral mass which is practically impassable except at Pulau Bawa, of which the W side has been washed smooth.
Caution.—Vessels approaching Pulau Pulau Hinako from the N must be careful to avoid the 5.9m patch about 4.7 miles NNE of the light structure of Pulau Hinako.