Complex sentence: Near the fort he constructed a sailing ship he named "Le Griffon" and used it to explore much of the Great Lakes.as far as modern Green Bay, Wisconsin in the following summer where he set up a trading post.
Split into simpler sentences: Near the fort he constructed a sailing ship he named "Le Griffon" and used it to explore much of the Great Lakes. He voyaged as far as modern Green Bay, Wisconsin in the following summer where he set up a trading post.