Main problem with any of the Silent Hunter games is the "protection" that Microsoft puts on "system" folders, including the "Program Files" and "Program Files (x86)" folders. This involves part of User Access Control (UAC), first encountered in Windows Vista. Any "unauthorized" edits of certain files in a Program Files folder will result in Windows rolling back the edits to previous states. In other words, you use JSGME (a WinXP program) to apply a mod, and Windows comes along and sees "cfg" files that were changed by JSGME, and rolls them back to the Stock versions. Even changes you make yourself will be rolled back. You end up with a partially activated mod, and strange behavior from the game. The workaround is to have SH4 installed in a folder you create yourself, not in the Program Files folders. This applies to whether you have a disk version, or a download version from any source.
No matter which mod you put in the game, Silent Hunter (especially SH4 v1.5) works on "spawning" the game's assets when the player is within a given range of about 25-30nm from the player's position. What can happen if you get in too close to some of the battle scenes, is that your presence interferes with timely spawning of the participants in the battle scene. Just be aware of that as you approach. In some of the scenarios, groups spawn well away from the battle scene and travel in. Other scenarios might have a group spawn near the engagement. RSRDC by lurker_hlb3 does have the best timing of any of the mods when it comes to major "historical" events happening.
