Complex sentence: At 1am on the 21st, the boats succeeded in boarding, carrying, and bringing off the largest galley, the "Prima", which had fifty oars and a crew of 257 men, and was under the command of Captain Patrizio Galleano.
Split into simpler sentences: At 1am on the 21st the boats succeeded in boarding, carrying, and bringing off the largest galley, the "Prima". She had fifty oars and a crew of 257 men, and was under the command of Captain Patrizio Galleano.