Change sub in Sub Command Missions.
 

I just started playing SUB COMMAND again after nearly ten years...I remember there was a code you could type in, or a certain keyboard button you could press while in the Mission Briefing page that would allow you to change your sub before the mission starts. In the IRAN mission, I want to change my sub from the 688(i) to the Seawolf. Does anyone remember how to do that? All the websites that listed this cheat for Sub Command, no longer exist...

UPDATE: I found it: In Mission window select the mission. Then on the sub screen is
the sub you have to use cause the arrow keys are in-active and
the player can't pick any sub. Well if you put the mouse cursor on
the sub name and press tab, the arrow that was in-active turns
red. The player can then take the mouse and click on the red arrow
that is now active and pick any sub from the list making it player's
choice instead of computer choice.

WARNING: The above post on how to change the sub in the MISSIONS section will only work if the Sub Command game is NOT patched to 1.08....If you added the patch, it will not work.

No it is possible, but the missions provided with it may not allow that (anymore). However, I have a mission called Bahama Bash in my list (not sure if it was made by Sonalysts or a community created mission I picked up somewhere) which allows me to change between Seawolf and several 688i. Afaik I have an unmodded but patched to 1.08 SC installed.

If they are still scripted in, the other platforms may not be designated as playable any more. But it should be an easy fix with the mission editor.