Sandbox/'cat conversion chart

This page is intended as a resource to supplement places like akashi-list, since it is not always clear which Saratoga can do which improvement. In particular, it makes it clear that fully remodeling Saratoga into a CVB as soon as possible is not necessarily the best plan. Hopefully the game will give Intrepid or Gambier Bay the ability to improve F4F-3 and F4F-4 soon and eliminate this roadblock.