The use of naval jargon in Trek may be at variance with RN or USN traditions, of course. After all, the shuttles aren't "boats" or "launches", either.
One might think that the TNG depiction of the craft, lacking warp engines and having fancy atmospheric flight systems in addition to impulse drive, might make her a "barge", in the sense of a "royal barge". In any case, there would appear to be a need to distinguish her from the shuttles that have significantly different propulsive capabilities. But "yacht" seems to go in an entirely wrong direction, being traditionally more capable in navigation than a "boat" or a "launch".