‘After 110 days at sea we were left with one canned ham, a crap load of white cake mix and some dehydrated fruits and vegetables,’ Jeffrey Knight, former US Navy submariner.
A submarine is a watercraft capable of independent operation underwater: it operates in an unforgiving, complex and highly pressurised environment.
A submarine sinks by taking in ocean water into large tanks. This weighs it down, allowing it to sink. A submarine takes in as much as it needs to go as low as it wants to. When it wants to come back up, it pumps out the water by pumping pressurized air into the tanks.
What is the longest time a submarine can remain underwater given the state of technology today?
‘My answer is regarding my experience on US nuclear subs,’ Jeffrey Knight, who is qualified on 4 different classes of US Navy submarines, says on Quora.
‘As I understand it now, most subs’ reactor cores are good for greater than 20 years. That makes the water, electricity, and good breathable air.
‘Crew size can be 110 to 140 plus any special ops types. Food for them can be stowed everywhere you can imagine. It was normal in the ‘70s and ‘80s to walk on cans and cases of food in berthing until we ate enough to take the level down to normal storage.
‘After 110 days at sea we were left with one canned ham, a crap load of white cake mix and some dehydrated fruits and vegetables. I know other boats experience the same.
‘Naval reactors have to be monitored and maintained to keep running. Unlike commercial reactors that are made to run nonstop with limited human intervention, the US Navy reactors are designed to shut down for any number of things if not addressed in a timely manner.
‘That said if the crew ran out of food and started dying off, the reactor and everything else would very soon after, start shutting down.
‘The boat would lose forward propulsion and depending on trim would very slowly surface or fall to the depths below.’
‘So, I would say 120 days max. Or 5 days after the coffee ran out.’
Photo credit: U.S. D.O.D. graphic by Ron Stern