As a subject matter expert in the field of submarine operations, I can provide an in-depth analysis of the factors that determine how long a submarine can stay submerged. The ability of a submarine to remain underwater is influenced by a variety of factors, including the availability of food and supplies, the type of submarine, its propulsion system, and the operational requirements.

Food and Supplies: Submarines are equipped with a supply of food and other necessities that can sustain the crew for extended periods. The typical submarine carries enough food to last for about 90 days, which is a standard supply duration. This allows a submarine to be self-sufficient for a significant amount of time, enabling it to operate underwater for up to three months without needing to resurface for resupply.

Type of Submarine: There are different types of submarines, such as diesel-electric, nuclear-powered, and air-independent propulsion (AIP) submarines. Diesel-electric submarines, which are no longer in use by the United States Navy, have a limited submerged endurance due to the need to surface or snorkel to recharge their batteries. Nuclear-powered submarines, on the other hand, can stay submerged for much longer periods due to their virtually unlimited power supply. AIP submarines use technologies like fuel cells or closed-cycle engines that allow them to operate underwater without the need for atmospheric oxygen, thus extending their submerged endurance.

Propulsion System: The propulsion system of a submarine plays a crucial role in determining its submerged endurance. Nuclear submarines, for instance, can operate for months without refueling, as nuclear reactors provide a continuous source of power. This is a significant advantage over diesel-electric submarines, which require oxygen from the atmosphere to recharge their batteries, limiting their submerged time to several days.

Operational Requirements: The mission profile of a submarine also affects how long it can stay underwater. Submarines on intelligence gathering or surveillance missions may need to remain submerged for extended periods to avoid detection. In contrast, submarines involved in search and rescue or other short-term missions may not need to stay submerged for as long.

Crew Endurance: The physical and psychological well-being of the crew is another important consideration. Prolonged periods in a confined space can affect crew morale and performance. Therefore, submarines are designed with living quarters, recreational facilities, and other amenities to ensure the crew's comfort and maintain operational effectiveness.

Maintenance and Repair: Submarines require regular maintenance and repair to keep their systems functioning optimally. While some maintenance can be performed underwater, more extensive repairs may necessitate surfacing or even returning to port.

Environmental Factors: Environmental conditions can also impact a submarine's ability to stay submerged. Extreme weather, underwater currents, and other factors can affect a submarine's operations and may require it to surface or change its operational plans.

In conclusion, while a submarine can theoretically stay underwater for up to three months with a standard food supply, the actual duration can vary based on the type of submarine, its propulsion system, operational requirements, crew endurance, maintenance needs, and environmental conditions.

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The limits on how long they can stay underwater are food and supplies. Submarines generally stock a 90-day supply of food, so they can spend three months underwater. The diesel-powered submarines (not now used by the United States Navy) had a limit of several days submerged.Feb 15, 2018read more >>