The number one enemy of productivity is distractions, either in the form of entertainment or things like chores and phone calls which feel productive but break up the day. Cruise ships are a remarkable way to eliminate all of those things. Efficiency can be so high on a cruise ship that you can schedule big projects, many small writing gigs or even the writing of a brand new book during the two-week cruise.
On a cruise ship, everything is taken care of for you. No time at all has to be allocated to cooking, choosing your meal, or to cleaning. You show up at the restaurant, in which all of the food is included, order whatever you want from the rotating menu, eat, and then immediately get up and get back to work. When you get back to your stateroom, it has been cleaned and the bed has been made. Today there appeared, with no explanation, a big platter of fruit, which will make a great snack while working.
Wifi is present everywhere, and has become much more affordable over the last few years. Some cruise lines have better and more affordable wifi options than others so do some research ahead of time and factor that into your cruise options.
If you get a stateroom with a window, it's quite comfortable to work from your room. If you need a snack, you can order room service, which is either free or carries a flat rate of $2 per order. Again, no cooking or cleaning up. If you prefer to work outside your room, there are always plenty of decent places to work around the cruise ship. Good options are the library, cardroom, or one of the nightclubs that are empty but unlocked during the day. Modern cruise ships are starting to be smarter about areas for guests to work, with power, USB ports and even in some cases, printers.
Despite working for most of the day, it's nice to have high-quality breaks. Meals on cruises can be quite long, and they seat you with random people. Most of the random people are probably not like the people you normally associate with, which can be a mixed bag, but allows for some shifts in perspective. If you go with a friend, you can debrief with him on your workday.
And, of course, you get to visit a bunch of new places. To really understand a city you may have to spend weeks or months there, but that doesn't mean that a day or two is completely useless. You can use the port stops to visit specific places, like the Fundacio Miro in Barcelona or the Hassan Mosque in Casablanca, or to just wander around and get a sneak preview of a new place. This is especially valuable for places like the Azores or Canary Islands, where you probably wouldn't otherwise find yourself.
If you're visiting a port that doesn't have anything you're excited about, you can also just find an internet cafe and handle phone calls and downloads that you weren't able to do on the ship. When you visit these ports, the process is incredibly efficient. The ship takes care of all of the immigration paperwork behind the scenes, so you get off the ship without having to go through customs. You're generally very close to downtown, versus airports which require trains or taxis, so you can immediately go do what you want to do. And unlike flights, you can get to the ship just a few minutes before the scheduled departure time and get on.
After returning to the ship, it's easy to immediately get back to work because there's no unpacking or settling in to be done. You just pick up your computer, head to your favorite workspace, and get rolling.
Cruising days are the best which is why you may want to choose the transatlantic cruises, which have five to seven days in the middle with no stops. The amount of work you can do during those days, completely free of distraction, is incredible. Doing the work feels easy because there's no friction or drain on willpower avoiding distraction. Frankly, if you're not into bingo and ballroom dancing, you may find there's not much for you to do on the ship other than work or read.
For most types of work, a cruise ship is a near-ideal environment. However, if you need to make a lot of phone calls or be connected to the internet all the time, it wouldn't make any sense to do. There's also a benefit to being around other people in your industry, and that generally isn't going to happen on a cruise ship, although you may not find it to be a problem for short term trips.
Take a look at transatlantic cruises, repositioning cruises or other long trips. They are the best ones to choose for a couple reasons. First, they have the highest ratio of sea day to port days, which gives you plenty of long blocks of time in which to work. Second, they're among the cheapest cruises available. If cruises were expensive, the added productivity boost may not be worth it, but at $30-50 per day, the cost is almost negligible. On the flip side, don't forget you've got to get home. You need to factor in the cost of a flight overseas and that be a big factor in your decisions.
Overall, just enjoy yourselves. Work for some is therapeutic. It can be a great "reset" and a way to get a big project completed with no pressures and distractions.