Complex sentence: It is a full-service marina/boatyard with 400 slips operating at 94% capacity in 1995, with many transient visitors filling slips vacated when homeport vessels are away.
Split into simpler sentences: It is a full-service marina/boatyard with 400 slips. It was operating at 94% capacity in 1995, with many transient visitors filling slips vacated when homeport vessels are away.