My family truly enjoyed staying on the Carpe Diem II. It was their favorite part of the trip, and I took them EVERYwhere, so that's saying something! Chad was super friendly and VERY responsive, and I contacted him a few times during our stay. He and Holly have made the yacht very homey and fun, with plenty of games, tv, a Bluetooth speaker, and plenty of comfy places to sit.
We enjoyed watching the boats go by and seeing the sunrises and sunsets over the water. The walk to the ferry was just far enough to get in our daily morning brisk walk to energize us for the day. We enjoyed the food from the nearby Style Cafe, and we cooked a few meals in the galley, which was well-stocked for our needs. Everyone slept great too. I will recommend this yacht to anyone staying in Boston who doesn't mind the brief walk to the ferry.
A word about public transit - the MBTA is currently (Oct 2022) overhauling the CharlieCard system (their scannable card used for riding public transit). The ferry currently does not have a CharlieCard reader, and thus the MBTA website insists that you purchase a paper CharlieTicket instead to ride the ferry. As I was unable to purchase a paper CharlieTicket ANYwhere (automated ticket machine, online, at any ticket booth), the ferry DID accept the CharlieCards as our ferry passes - all we had to do was show it to them when de-boarding. I think the MBTA has done away with the paper tickets without having updated either the website or anyone at customer service. ANYWAY, to purchase a 7-day CharlieCard, which gives you unlimited rides on the subway, buses, and ferry for 7 days, just to the automated ticket machine at the T station at Long Wharf (labeled "T Aquarium"), select Buy a Charlie Card, and select 7-Day Pass for $22.50 (less for seniors and students). Print a receipt as well in case the ferry employees ask for it. I hope this helps someone :)