My idea for the purpose built technical research vessels being built from the keel up, was to have each vessel have specific areas of operation... with the ability to outrun anything they couldn't outgun. and from my time in the navy, i don't remember if you can convert a ship's propulsion systems like that.
I'm not shooting this down, hell, i'm going to use this info you've give me CA and work it into my mini-article.
I just need something that i can use... at one time the original idea for the new spy vessels, they were really stealhly submarines that would have special sensors they would trail behind them that would pick up signals and data. That when they surface in the nighttime, they'd have running lights and the like that would make them look like a fishing boat or something (yes i got the idea from "up periscope").
Sorry for the brief posts... i'm about to run out the door to a VA Medical Appointment.