Small boats risk conflicts with bigger ships if they follow the shipping lanes. Sections of lanes exist which can be shallow or have some kind of obstruction (such as sand banks). This threat is greatest when passing some narrows, such as between islands in the Indian Ocean (e.g. in Indonesia) as well as between islands in the Pacific (e.g. near the Marquesas islands, Tahiti) Some shipping lanes, such as the Straits of Malacca off Indonesia and Malaysia, and the waters off Somalia, are frequented by pirates operating independently or as privateers (for companies and countries).