Another dumb question
 

I have seen a couple of times talk about changeing torpedos at the start of a mission..How do you do this and whats the best???

Well, you've got that panel you access in port where you hire new crewmembers and fit new equipment. It also has a tab for torpedoes. As a matter of fact that's where you reload your empty tubes. You can even use it to spend renown for the more exotic torpedo types.