A cargo shipwreck is a type of maritime disaster in which a large cargo vessel has been wrecked due to a variety of causes, such as storms, collisions, or running aground. The term 'REEF' is used to describe a submerged rock, coral, or sandbar that can cause a ship to become grounded and eventually sink. Reefs are often difficult to detect and can be hazardous to ships navigating in shallow waters.