Well, to get the terminology on track (or under sail), technically a boat is a small craft like a cabin cruiser or fishing vessel, so I'd say the reference should be to travelling by ship. The only regularly scheduled trans-Atlantic passenger service is provided by Cunard's Queen Mary 2, which makes the trip in about 5 days. Other lines offer transatlantic trips on so-called "positioning voyages", when a ship is moved from its winter runs in (e.g.) the Mediterranean to a summer posting in the Caribbean. These ships are not specifically designed for transocean cruising so they travel more slowly; a crossing might take 7 or 8 days. Nearly everyone I have spoken with who has made a crossing on the QE2 thought it was one of the best experiences of their lives. The QM2 is even larger and more luxurious, so it should be a "don't miss" trip.