How are submarines different from before?

Modern submarines differ significantly from their predecessors due to advancements in technology, materials, and design. Contemporary submarines often feature stealth capabilities, allowing them to operate undetected, and are equipped with advanced sonar systems for improved navigation and target detection. Additionally, advancements in propulsion, such as nuclear power, enable longer missions without the need for surface refueling. Enhanced automation and digital systems also streamline operations and improve overall efficiency compared to older models.