Complex sentence: At Oowan, Kabayama sent his some officers to Naha in order to fulfill his promise, while he disembarked his other men, because he heard that there was a chain at the entrance of Naha harbor.
Split into simpler sentences: At Oowan, Kabayama sent his some officers to Naha, in order to fulfill his promise. But he disembarked other men, because he heard that there was a chain at the entrance of Naha harbor.