Which naval officer's contributions significantly advanced American naval weaponry in the 19th century?

The answer focuses on John Dahlgren, whose significant contributions notably advanced American naval weaponry during the 19th century. He was an influential naval officer recognized for developing the Dahlgren gun, a type of smoothbore cannon that was revolutionary in its design and effectiveness. This artillery piece was crucial during the Civil War, providing the Navy with a competitive edge in naval warfare.

Dahlgren's innovations didn't just stop at the weapon itself; he also contributed to advancements in naval tactics and logistics that improved how the Navy operated during combat. His emphasis on gunnery training for naval personnel helped ensure that crews could effectively utilize these advanced weapons systems.

In contrast, while other officers like John Paul Jones and Stephen Decatur made significant contributions to naval history and tactics, and George Dewey is noted for his leadership during the Spanish-American War, none played a role in weaponry development that matched the impact of Dahlgren's innovations in the 19th century. Thus, the choice of John Dahlgren accurately highlights the officer who most directly advanced naval weaponry during that period.