I run a digital interactive software company with employees in the U.S. and abroad. On the boat I have WIFI with an external antenna access/point networked to a local WIFI network for multiple devices. If anybody wants to know how to do this, just ask, it greatly extends the range and signal strength.
During the summer we typically run to the boat Thursday night and stay through Monday. The other days I work out of my home office.
Working from a laptop, even a really good one, doesn't give you the screen real estate you get in an office and that does cost you some productivity. It is also going to give you neck and back cramps after long hours. The other challenge is that marine WIFI is generally "recreational" and is not all that reliable, or fast - if you're used to making video Skype calls, you may have troubles.
In my business we transfer a lot of files, artwork, chunks of code, etc. to do this easily I remote desktop into my office to take advantage of the bandwidth.
That being said, it's a real pleasure to be in a meeting where everyone else is stuck in an office, and you're on the boat. I generally don't tell clients where I am