I have been doing some research around these for a custom boat build. They are pretty heavy and bulky and require a fair bit of battery power although they are getting smaller for smaller boats. Looking at 400 pounds plus probably 3 batteries for the Seakeeper 2. That said, they are supposed to work incredibly well, both underway and when moving slowly or staying on a spot. Pretty much every review on them raves about their ability to minimize roll in rough weather.