Correct me if I'm wrong but it looks to me that you have to be on line to use it. I don't see anyway to download the information to a memory stick for use on the boat computer.
80% of ActiveCaptain use today is offline using one of the navigation products that license our data (for free). Included with that is our own ActiveCaptain Companion app (also free) for iOS, Android, Windows, and Macintosh OSX. The Companion is a different kind of thing - I wrote newsletter item about it recently because it has been misunderstood:
https://activecaptain.com/newsletters/2014-11-26.php
20% of ActiveCaptain use it on the website. That is the only use today that is "online". Using ActiveCaptain on any of the apps that have it built in requires no internet connection at all. Every marina, anchorage, bridge, hazard, etc along with all reviews are kept offline - our entire website. When you have an internet connection, you can synchronize the app with our server to make sure you have the latest info. What gets downloaded is everything that has changed since the last time you sync'd it. It's pretty quick and should be done every day before taking off underway - it will take under a minute of sync time like that.
At the Miami Boat Show in a couple of months, the first manufacturer is releasing ActiveCaptain on their MFD's built in and offline (releasing, not announcing). Another might be announcing support and a third is working out the details. The fourth (there are only 4 major manufacturers) surely knows about it but hasn't moved forward. We believe that having ActiveCaptain on chartplotters will reduce website use down to 10%.
And when the OpenCPN PlugIn is released (January?), that'll knock web site use by another 3-5% bringing it down to about 5% of total use.
The bottom line...our goal is to have 0% of boaters using the website for planning and analysis. For pure ActiveCaptain exploration, you should be using it on your navigation product. There are plenty to choose from and if yours doesn't support ActiveCaptain, you can replace it or augment it with a variety that do.