What device was first used to prevent early submarines from running blind while submerged?

The device that was first used to prevent early submarines from running blind while submerged is the periscope. The periscope allows submariners to observe the surface environment without exposing the entire submarine. By using mirrors and lenses, it provides a view above the waterline while the vessel remains submerged. This capability was crucial for submarines, especially during World War I and World War II, as it enabled them to detect enemy ships, navigate, and plan tactics safely and effectively without revealing their position.

The other devices listed, while important in the evolution of naval warfare, came later or serve different purposes. Sonar, for example, is designed for detecting underwater objects by utilizing sound waves, and sonobuoys are specialized devices for tracking submarines but are not used to navigate while submerged. An echo locator is related to tracking and depth measurement, but it does not provide direct visibility of surface conditions like the periscope does.