Submarine propulsion refers to the systems that enable submarines to move through water. The most common types of propulsion are diesel-electric and nuclear. Diesel-electric submarines use diesel engines to charge batteries, which then power electric motors for underwater movement. In contrast, nuclear submarines use nuclear reactors to generate steam, which drives turbines for propulsion, allowing for longer underwater endurance. The choice of propulsion affects a submarine's speed, range, and stealth capabilities. Nuclear submarines can operate for extended periods without surfacing, while diesel-electric submarines are quieter but require periodic surfacing to recharge their batteries. Each type has its advantages depending on the mission requirements.