There was 1 Federation ship when Hudson took over, and there was no sale on it for his ascension to the Presidency, so I'm not sure what it would take for that to happen. And it would be on the Federal Gun/Drop/Assault ships, not the Corvette, so don't get your hopes up and start working on those ranks. It's not that hard to get rank, look for Federation faction missions that give Medium or High Reputation gain, that's how you get naval rank progression quickly. Pay will often be pitiful, but you are trying to get rank, not get rich, right?