I thought it was a `fly code?
There's a kind of height restriction in SS - your ship just gets stuck in the air. Same restriction is in environments on MP regarding how far you can sail off the chart limit before you'll be "stuck in the invisible wall". So you have to restart with your ship.
That's normal, obviously can't be & won't be fixed/changed in SS08.
Besides it's a Ship Simulator & Titanic never reached neither New York nor Mars.