Complex sentence: The reports turned out to be largely unfounded but while on Sable, Dix assisted in a shipwreck rescue and upon her return to Boston, she led a successful campaign to send upgraded lifesaving equipment to the island.
Split into simpler sentences: The reports turned out to be largely unfounded but while on Sable, Dix assisted in a shipwreck rescue. Upon her return to Boston, she led a successful campaign to send upgraded lifesaving equipment to the island.