Torpedoes used as mines?

Hello,

Yesterday when i was playing SHV, my first officer was telling me that the torpedo guy had an idea to change our torpedoes into surface mines or something like that and that i should go talk to him about it. Onfortunatly at the moment i was talking to my first officer, the boat was rocking so much that the conversation screen disappeared before he was finished talking.

After that i went to the torpedo guy and he had absolutely no conversation options.

So my question now is: does anyone know if it is possible to change a torpedo into a surface mine?

I was really excited when i read what the first officer said because i thought it would be really awesome to lay some minetorpedoes in front of an upcoming convoy.