If this is known sorry, but while saving a large ship and getting Warning Server does not answer message I checked how much CPU javaw.exe was using and found that MsMpEng.exe was using over 50%. Did some digging on Microsoft Security Essentials and found that by adding two excludtions most of the problem went away. I added msmpeng.exe and javaw.exe to the Excluded processes and Excluded files and Locations.
Hope helps some server crashes.
Hope helps some server crashes.