Complex sentence: Usually, a brand new ship sailed first with closed gun ports to give the captain and crew an idea of how it would handle, as each ship built in the 17th century handled a little differently from every other ship.
Split into simpler sentences: Usually, a brand new ship sailed first with closed gun ports to give the captain and crew an idea of how it would handle. Each ship built in the 17th century handled a little differently from every other ship.