The first use of submarines, and the appearance of "modern" submarines

Question

The first submarines surfaced (excuse the pun) during or around the American Civil War. The question I have comes in a few parts:

1. Did the submarines seen in the American Civil War prompt any change in tactics for surface ships to counter them?

2. What was the first "modern" military submarine, and what effect did it have on military thinking at the time?

3. While the first ship to have been sunk by a submarine was the USS Housatonic, the submarine in question was, understandably, extremely basic. When was the first successful attack by "modern"* submarine, and what ship was attacked?

4. Finally, when originally inventing the submarine was there an aim other than gaining military advantage?

*Modern = motorized, with powered torpedoes etc.

Answer 1

Actually, no... the first submarines used in warfare appeared in the Revolutionary War, and two more were deployed (unsuccessfully) by the US in the War of 1812.

1) No, because they weren't very practical or successful until John Phillip Holland and Electric Boat perfected the battle submarine at the turn of the century.

2) The first modern military submarine was the Toro Submarino launched in 1880 - it had a torpedo tube and a gas/electric drive system.

3) The first submarine kill in actual combat was by the German U-21 in 1914.

4) The very first operable submarine was built to amuse King James I by Cornelius Drebble. The first successful powered submarine was the Ictineo II, whose inventor fitted it with pneumatic cannon in an attempt to secure funding from the Spanish navy... so it was designed as a development platform for a weapon of war.

Answer 2

Before WWI torpedoes and torpedo boats had a much greater impact on naval tactics than submarines which were still generally considered a bit of a novelty. The Revolutionary War and Civil War examples were essentially weapons of desperation against a vastly superior blockading force and not particularly successful.

Torpedo Boats were a different story as a swarm of very cheap but fast power boats could pose a genuine threat to battleships which at the time were the most powerful (and expensive) weapons ever invented. As a result 'Torpedo Boat Destroyers' were built with smaller fast firing guns to deal with the threat (the name was eventually shortened to just 'Destroyer'). More thought was given to secondary armaments on capital ships, armour below the waterline was strengthened and technologies like torpedo nets and later torpedo bulges were invented.

Submarines didn't really have much effect on tactics or outcomes until WWI. Even then, the German U-Boats behaved more like surface raiders that could dive to escape attack rather than as submerged ambushers where their speed, range and visibility were heavily restricted.

Arguably it's not until the Type VII U-Boat in WWII and the invention of hydrophones, attack periscopes, deep diving hulls and torpedo data computers that you see a truly 'modern' submarine designed with an emphasis on submerged torpedo attacks.