Submarine FAQ — Your Questions Answered
Everything you've ever wanted to know about submarines — from how deep they can dive to what the crew eats for dinner. These are the most frequently asked questions about submarines, answered by experts.
How deep can submarines go?
Military submarines typically operate at depths of 200-500 meters, with some reaching 600 meters or more. Research submersibles go much deeper — the DSV Limiting Factor has reached 10,928 meters in the Mariana Trench. Tourist submarines generally stay within 30-100 meters. The exact maximum depth of military submarines is classified, but the theoretical crush depth is typically 1.5-2 times the rated operating depth.
How long can a submarine stay submerged?
Nuclear-powered submarines can stay submerged for months — their endurance is limited only by food supplies and crew morale, not fuel or oxygen. The record for continuous submerged operation is 111 days (set by HMS Warspite in 1982-83). Conventional diesel-electric submarines must surface or snorkel every few days to recharge batteries, though modern AIP (Air-Independent Propulsion) submarines can stay submerged for 2-3 weeks.
Can civilians buy a submarine?
Yes, civilians can legally purchase personal submersibles. Companies like Triton Submarines, U-Boat Worx, and SEAmagine manufacture private submarines starting from around $1.2 million for a compact two-seater. Luxury submarine yachts can cost $25 million to over $2 billion. However, you cannot buy a military submarine — decommissioned military subs are typically scrapped or turned into museums.
How much does a submarine cost?
Costs vary enormously. A personal submersible starts at about $1.2 million. Mid-range tourist submarines cost $5-30 million. A modern conventional military submarine (like the Type 214) costs $350-600 million. Nuclear attack submarines like the Virginia class cost approximately $3.4 billion each. Ballistic missile submarines are the most expensive — the new Columbia class will cost around $8.5 billion per boat.
What do submarine crews eat?
Submarine food is generally considered the best in the military. Fresh fruits, vegetables, and milk are available for the first two weeks of a patrol, after which crews rely on frozen and canned provisions. Submarines serve four meals a day including "midrats" at midnight. The US Navy allocates about $12.85 per person per day for submarine food — the highest in any service branch. Sunday dinners often feature steak or lobster.
Can submarines be detected?
Yes, but it is extremely difficult. Submarines are detected primarily through sound (passive sonar listening for engine noise, propeller cavitation, and mechanical vibrations) and active sonar (sending out sound pulses and listening for echoes). Other methods include magnetic anomaly detection (MAD), thermal wake detection, and satellite-based ocean surface disturbance analysis. Modern submarines are designed to be as quiet as possible — at slow speeds, some are quieter than ambient ocean noise.
How do submarines navigate underwater?
Submarines use inertial navigation systems (INS) — extremely precise gyroscopes and accelerometers that track every movement from a known starting position. Modern systems can maintain accuracy for weeks without external input. Submarines also use bottom-contour matching (comparing seafloor terrain to charts), depth soundings, and occasionally rise to periscope depth to get GPS fixes. Celestial navigation through the periscope is still taught as a backup.
What happens if a submarine loses all power?
Submarines have multiple backup power systems: emergency diesel generators, battery banks, and manual backup systems. If all electrical power is lost, the crew can still blow the main ballast tanks using stored high-pressure air to bring the submarine to the surface. Emergency procedures are drilled regularly, and critical systems like ballast tank blowing can be operated mechanically without electricity.
How do submarines get fresh air?
Nuclear submarines produce their own oxygen by electrolysis — splitting seawater (H2O) into hydrogen and oxygen using electrical power. Carbon dioxide is removed by chemical scrubbers using amine solutions. Trace contaminants are filtered by activated carbon beds and catalytic burners. The air is continuously monitored for oxygen levels, CO2, hydrogen, carbon monoxide, and other gases. Conventional submarines must snorkel (run a tube to the surface) to exchange air with the atmosphere.
Are submarine tours safe?
Commercially operated tourist submarines have an excellent safety record with zero passenger fatalities in decades of operation. These submarines are classified and inspected by independent organizations (DNV, Lloyd's Register), operate at shallow depths (typically under 50 meters), and carry extensive safety systems. They should not be confused with uncertified experimental submersibles — the OceanGate Titan implosion in 2023 involved a vessel that had not undergone independent safety certification.
How fast can submarines go?
Most military submarines have a maximum submerged speed of 25-33 knots (46-61 km/h). The fastest submarine ever built was the Soviet Alfa class, which could reportedly reach 41 knots (76 km/h) thanks to its liquid metal reactor and titanium hull. Surface speed is generally slower than submerged speed because submarines are designed to be hydrodynamically efficient underwater. Tourist and private submarines are much slower, typically 3-5 knots.
How do submarines communicate?
Radio waves do not penetrate seawater well, making submarine communication challenging. Very Low Frequency (VLF) radio can reach submarines at shallow depths. Extremely Low Frequency (ELF) can penetrate deeper but transmits data very slowly (minutes per character). Submarines can also trail a buoy on a wire to receive satellite communications near the surface. To transmit, a submarine must generally come to periscope depth — which risks detection.
How many people serve on a submarine?
Crew sizes vary dramatically. A small tourist submarine might carry 2-3 crew and 20-64 passengers. A conventional military submarine like the German Type 212 has a crew of about 27. Nuclear attack submarines carry 100-135 crew members, while ballistic missile submarines can have crews of 150-160. The largest submarines ever built — the Russian Typhoon class — carried 160 crew in relatively spacious conditions by submarine standards.
What is the biggest submarine ever built?
The Soviet Typhoon class (Project 941 Akula) holds the record at 175 meters long with a submerged displacement of 48,000 tons. For comparison, that is longer than most World War II battleships. The Typhoon was designed to launch ballistic missiles from beneath Arctic ice. Its double-hull design created enough internal space for a sauna, swimming pool, and relatively comfortable crew quarters.
Do submarines have windows?
Military submarines do not have windows — they rely entirely on sonar, radar, periscopes, and electronic sensors to "see." Windows would be a structural weakness in the pressure hull. However, tourist and private submarines often feature large acrylic viewports or even fully transparent pressure spheres. Research submersibles like Alvin have small but thick acrylic viewports rated for extreme depths.
Can you survive a submarine implosion?
No. A submarine implosion occurs when the hull is crushed by water pressure after exceeding its structural limits. The collapse happens in milliseconds — faster than the human nervous system can register. The energy released is enormous; the Kursk's second explosion was detected by seismographs across Europe. An implosion at depth is instantly fatal for everyone aboard.
How do you become a submariner?
In most navies, you first enlist or receive a commission in the navy, then apply for submarine service. Candidates undergo psychological screening for claustrophobia and ability to handle stress. Selected personnel attend submarine school (several months) before being assigned to a boat, where they must complete a qualification process ("earning your dolphins") that takes 6-12 months and requires learning every system on the submarine.
What is the difference between a submarine and a submersible?
A submarine is a vessel that can operate independently for extended periods — it has its own propulsion, power generation, navigation, and life support. A submersible is smaller, typically battery-powered with limited endurance, and requires a support ship for launch, recovery, and long-distance transit. All tourist and research vessels are technically submersibles, not submarines. Only military vessels are true submarines.
Still Have Questions?
Our comprehensive guides cover every aspect of submarines in much greater detail. Whether you're interested in nuclear propulsion, safety systems, buying a personal submarine, or just exploring the undersea world — we have you covered.