The URF has 4 main classes of ships:
Viper Class ships are one-man fighters. They don't have FTL but they are very manuverable.
They are usually used in a group, since a single Viper isn't very powerful.
Patrol Class ships are used, as their name indicates, as in-system patrol craft. They have FTL, but their real strength is high speed and manuverability at sublight speeds. Unlike the Vipers, the Patrol ships have deflector shields. Some of them also have cloaking devices, but they don't really work well in Patrol ships due to power limits. Their crew size varies from a dozen to over 50.
Capital Class ships are the backbone of the URF fleet. They are used in deep-space exploration, large-scale battles, and nearly anything else. Their crew size ranges from 100 to over 1,000. They are highly automated, and usually have a number of droids. They have a huge array of weapons, including energy beams, powerful shields, and a reliable cloaking device.
Devastator Class ships are the powerhouses of the fleet. The URF has 6 of them. They are HUGE, and their crew consists of thousands of people and hundreds of droids. They are crammed with every weapon known. However, their very size and power is also their weakness. One of the people in charge of financing for the Devastators remarked that if New Romanar was attacked, it might be cheaper to let them destroy the planet rather than risk the super-ships. He claimed to be joking, but those behemoths ARE incredibly costly, both to build and to operate. The Romanar generals point to them as a symbol of New Romanar's power, but in every conflict so far, they've always sent multiple Capital ships and kept the Devastators in orbit.