Complex sentence: The Confederate gunboats "Bayou City" and "Neptune" arrived shortly thereafter, and while the "Neptune" was disabled, "Bayou City" succeeded in boarding the USS "Harriet Lane".
Split into simpler sentences: The Confederate gunboats "Bayou City" and "Neptune" arrived shortly thereafter. While the "Neptune" was disabled, "Bayou City" succeeded in boarding the USS "Harriet Lane".