Hi there xolovestephi
Welcome to
The playable surface vessels can present a challenge in finding missions, but you can edit any of the single missions you can find online that use the submarine that the Yamato is built on. All you have to do is make certain the you have the names correct and the "Height=0". Most of the submarine missions start with the submarine set to periscope depth. The Yamato, being a Japanese vessel, was built in the German campaign so that its own IJN fleet would not shoot at it. The problem is that there are no included single missions for the UBoats side. There are some, such as
http://www.subsim.com/radioroom/show...213#post851213
The download link for SubSim is
http://www.subsim.com/radioroom/down...o=file&id=4053
Notice the "misge" extension on the mission files. That's what makes them show on the German side of the SH4 menu. You can use the mission editor to do some of the work for you, but it would probably be easier to just use a text editor. Let us know if you want some help to alter some of those files, and if you do, let us know which Yamato mod you're using...