Complex sentence: In May 1918, the "Zealandia" was requisitioned as an Allied troopship and it was among the ships used to transport the American Expeditionary Force from the east coast of the US to France.
Split into simpler sentences: In May 1918 "Zealandia" was requisitioned as an Allied troopship. She was among the ships used to transport the American Expeditionary Force from the east coast of the USA to France.