Complex sentence: In 1984 "Explorer" navigated the Northwest Passage, and in 1989 it was involved in the rescue of the crew of an Argentinian supply ship that had hit a rock ledge off Anvers Island, Antarctica.
Split into simpler sentences: In 1984 "Explorer" navigated the Northwest Passage. In 1989 she was involved in the rescue of the crew of an Argentinian supply ship that had hit a rock ledge off Anvers Island, Antarctica.