So understandably some players in Blitz games are not experienced in the game and it is a first stop of sorts.  Inevitably, in one of your earliest games you'll see a Kita or some big strong CA dump a bunch of torps overboard and kill an enemy ship effortlessly and you'll say to yourself 'man, those torpedoes are deadly. I've got to get me some of those.'  There's just a bit more to it than that to consider.

Frequently, in Blitz games that I've been in of late I've come across a myriad of players bragging about their high team attack contributions, and at the same time not giving a second thought to the fact that they're walking out of a good number of rounds with less than a thousand XP.  It seems that one lesson the tutorial doesn't teach, and some seem to ignore completely, is logic when it comes to dropping their torp load.  It happens with guns as well, but most focus rightly should be on torps.

In the most common scenario, the battle just started and many team members rush straight forward to meet the enemy in hobbit rooms.  Inevitably there is someone, who facepalmingly often is in a CA, who will arbitrarily drop a salvo of torps on fast speed thinking if they're faster they'll reach the enemy line more quickly, completely ignoring the fact that there is 2-3 smaller allied ships directly in the path of his torpedoes.  He might hit and sink an enemy ship and be proud about racking up 10k attack, ignoring the fact that he destroyed a friendly ship and damaged another.

While the damage done to friendlies doesn't get quantified in the battle on your damage, it most certainly hits where it hurts as it causes a rather large xp penalty to yourself, and on top of that your damaging of allied ships makes it that much easier for the enemy team to defeat yours.

Don't mistake this as pointed hate towards blitz ships using torpedoes.  I get it, even with CAs sometimes.  The threat from SS doesn't exist so there's no need for HHs, and the threat from CVs is often minimal so AA isn't as critical as other game modes.  

That said, a concept that needs to be paid much more attention to, especially by newer players, is being mindful before hitting the Space Bar.  Estimate the path and speed of your torpedoes.  Is a friendly ship likely to be in the path?  Don't shoot, ask an approaching ship to turn away, or just wait and move yourself to a better position.  Your attacks will be more successful against enemy ships as a result of you being more aware of your surroundings rather than just pointing and shooting, and your teammates will be thankful that you're being tactful and will be able to support you because they can work with you, not work around you.