Before WWI it wasn't uncommon for capital ships to have batteries of torpedo tubes below the waterline. They were mostly omitted in post-war designs since at Jutland none of the British or German battleships scored hits with their torpedoes and it became obvious that the drawbacks outweighed the potential benefits: You need to get in close to use them and battleships are expensive and important. However HMS Rodney may have scored a hit on the Bismarck with a torpedo, conversely one of HMS Nelson's torpedo rooms was hit by a Italian torpedo and suffered major flooding.
Incineration said:
Then again, Graf Zeppelin has multiple guns and can neither equip any, nor does she have a barrage skill.
Graf Zeppelin's guns are a great example of "superior German engineering." She was originally going to have 8 individual guns mounted in pairs on each quarter. The head designer suggested that instead they could save weight and space by switching them to a single double mount on each quarter, but the navy misinterpreted this and increased the number of guns to 16 instead.
