Hazard for ships can refer to two different things: a REEF and a leeshore. A REEF is a ridge of rocks or coral that lies close to the surface of the water, making it dangerous for ships to pass over. A leeshore is an area of land that is close to the shoreline and can cause a ship to be pushed onto the shore by strong winds or currents. Both of these hazards can cause serious damage to ships and their cargo.