SIEV X was the name assigned by Australian authorities to an Indonesian fishing boat carrying over 400 asylum seekers en route to Australia, which capsized in international waters with great loss of life on 19 October 2001. SIEV stands for Suspected Irregular Entry Vessel and is the acronym used by the surveillance authority for any boat that has entered Australian waters without prior authorisation. The X is a designation used where a tracking number has not yet been assigned, in accordance with Australian Government orders.