User blog comment:Maxfield, the Garryfish with PTSD/Base Collapsing, Don't know why... Help?/@comment-1461049-20170305210159

When you add or remove a base component such as a hull reinforcement or moonpool, you'll see how much hull integrity you have in the upper left-hand corner. You'll want that number to be positive. And even if it is positive, your base will still be flooded until you take your repair tool and fix all the holes that appeared. Sounds to me like you didn't close the holes after you added the reinforcements.