Topic: Fed Battle Tug Unity
The Federation Battle Tug is a ship with an interesting history. To quote from the 1979 Designer's Edition of SFB:
In a controversial program, the Federation Star Fleet developed the "Battle Pod". Its purpose (according to its supporters) was to enable the fleet, in an emergency, to convert Tugs into Heavy Cruisers.
I've always loved the idea of this ship. The battle pods would be warehoused at starbases in border regions, awaiting the outbreak of hostilities. When such occurred, tugs could be converted to warships in a matter of hours. Note that while the writeup quoted above compares the battle tug to a heavy cruiser, the BT's firepower is more nearly equivalent to a Fed battlecruiser like the New Jersey.
As time went on and more supplements for SFB were published, BTs were created for all the major races, but in "my" SFU, only the Federation built battle pods, most likely at the urging of some crazed admiral with a nickname like "Crackerjack" or "Buckshot". The BT handles like the '66 Dodge Monaco my dad had when I was a kid, but like the Monaco, when you see it coming, you get out of the way.