Complex sentence: The "Racer", of six guns, became "Shelburne"; the "Dolphin" retained her name; lastly, it is not clear what became of "Arab", of seven guns, which too had put up some resistance.
Split into simpler sentences: The "Racer", of six guns, became "Shelburne"; the "Dolphin" retained her name. Lastly, it is not clear what became of "Arab", of seven guns, which too had put up some resistance.