Sub selection
 

I have designed a single mission with a single ship and a UBoat but even when setting the time period I still get only the Type II to choose. How to have the user to choose between multiple subs to play the mission? I did put other "Human Control" Uboats in the map but still I can only choose the Type IIs

What is the date of your mission, and the date the player sub enters? You can only have one sub set "Human controlled" per mission. The choice comes from the mission start screen, not the mis file. If you date the mission file, or the submarine entry date too early, you sometimes do not get a full Roster of choices. If you put multiple player subs in, you force the game to the first boat - if it runs at all.