Complex sentence: On 18 April, "Long" sailed for the invasion of the Hollandia (currently known as Jayapura) area; she entered Humboldt Bay 22 April, made an exploratory sweep, and then fired a close-in preinvasion bombardment.
Split into simpler sentences: On 18 April, "Long" sailed for the invasion of the Hollandia (currently known as Jayapura) area. She entered Humboldt Bay 22 April, made an exploratory sweep, then fired a close-in preinvasion bombardment.