Fuel tanker
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At least one fuel tanker escaped the Fall of the Twelve Colonies and jjoined with the Fleet. It remained loyal to Commander William Adama during the short-lived schism between the military and civillian governments following the attempt on Adama's life by Cylon infiltrator Sharon "Boomer" Valerii (Kobol's Last Gleaming, Part II).
The unnamed tanker was damaged in a collision with a fuel tanker during this time due to the incompetent oversight of recently promoted Captain George Birch, CAG for Galactica in Lee Adama's absence (Home, Part I).