Odds of Hanging On
Don't crash and sink your boat and you're off to a good start.
Your odds are fine as long as people buy tickets on your cruise line, or you catch plenty of fish, or—if you're in the military—you make rank appropriately. In the end, your boat has to produce. You need passengers. You need a catch. You need to track down those terrorists and blow them out of the water.
Get enough people, marine life, or prisoners of war on board and you can keep sailing until you reach that glorious horizon known as retirement.