Why will a third of the ships be destroyed when the star falls into the ocean?
When the star falls into the ocean, a third of the sea becomes blood and a third of sea life dies. Because it strikes an area with shipping lanes, a third of the ships are destroyed in that single event.
Les explains that a great object from outer space will strike the earth and land in the ocean. That area evidently contains shipping lanes, so many ships are destroyed in the same event. The sea becomes blood, a third of the living creatures in the sea die, and a third part of shipping is affected. He then notes the next star falls on rivers and fountains of water, attacking fresh water, and compares it to Egypt, where Moses turned the Nile to blood, prompting Egyptians to dig wells, and then God affected even the well water.