Complex sentence: In order to have a chance of hitting their target, PT boats had to close to within 2 miles (3.2 km) for a shot, well within the gun range of destroyers; at this distance, a target could easily maneuver to avoid being hit.
Split into simpler sentences: In order to have a chance of hitting their target, PT boats had to close to within 2 miles (3.2 km) for a shot, well within the gun range of destroyers. At this distance, a target could easily maneuver to avoid being hit.