Compared to torpedoes, submarine technology was far more mature. As early as the American Revolutionary War, Americans had already tinkered together early submarines.
Later, during the War of the Sixth Coalition, the American Fulton built the first submarine capable of actual combat, the Nautilus, with Napoleon's support.
It was not the one from Twenty Thousand Leagues Under the Sea, of course, but even so, its influence was evident.
The world only knew that Napoleon had rejected Fulton's steamboat and lost the war, but it did not know that the two had collaborated long before that.
The Nautilus failed to sink a single British warship, and Fulton even tried to sell its secrets to the British, creating a deep rift between the French and Fulton.
In 1804, Fulton went to Britain and lavishly boasted to the then British prime minister, William Pitt, about his great weapon, only to meet fierce opposition from the Royal Navy.
The naval minister at the time called Fulton's submarine a dangerous "toy" and declared that if the Nautilus could sink the Victory, he would fill his entire estate with Nautiluses.
In this iteration of 1848, a Bavarian artillery sergeant named William Bauer invented an entirely new submarine that could dive to a depth of sixty meters and travel underwater.
Franz naturally would not let such a capable man slip away, though he only intended to draw on Bauer's experience.
As times changed, the greatest value of unconventional inventors like this, when researching large and sophisticated equipment, was in providing ideas. Raising standards and achieving mass production still required genuine professionals to perform repeated calculations.
Personally, Friedrich rather appreciated naval mines. He felt that both submarines and torpedoes were a little too illusory, whereas mines were much more practical.
In fact, Friedrich believed that if enough mines