Which ship is considered the first true submarine?

The Turtle is recognized as the first true submarine due to its innovative design and operational capabilities during the American Revolutionary War. Developed by David Bushnell in 1775, the Turtle was constructed to be a one-man submarine that could remain submerged and navigate underwater. Its primary mission was to attach explosives to enemy ships, marking a key advancement in naval warfare. The Turtle was unique in that it utilized a hand-cranked propeller for propulsion and had a design that allowed it to dive and surface, distinguishing it from earlier attempts at underwater craft.

Other options, while significant in their own right, do not hold the same distinction as the Turtle. Holland VI, for instance, is credited with being one of the first modern submarines in the early 20th century, and Dolphin was notable for its design but not for pioneering underwater warfare. The Resurgence, while likely a reference to a specific class of submarine, does not align with the historical significance of being the "first" in the sense that the Turtle does.