Prison Barge
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An old-style class of liner relegated to support roles or adopted as cargo transports. Following the destruction of the Twelve Colonies however at least one of these old vessels was transformed into a prison barge, where criminals were detained.
Prisoners on such a vessel are sometimes referred to (impolitely) as Barge Lice (Baltar's Escape).
Note
In the new Battlestar Galactica, the Astral Queen is a direct homage to this type of vessel.