Well, if you keep OLC and install acm reloaded and acm lite map also then you'll get your U-Boat contact back. ACM Reloaded makes changes to the OLC UI, mainly graphical. I use it and love it.
This order in JSGME (read the documentation that comes with the mods to avoid conflicts):
OLC 'Gold' MkII ~ Option 3 ~ Enviroment with EDE and GUI (Pick what ever option you want, this is just my choice)
OLC 'Gold' MkII ~ MkIId Update (Enable After MkIIc)
OLC 'Gold' MkII ~ Flat Sun Fix (Add this if your sun doesn't shine)
ACM Reloaded for OLC 'Gold' MkII
ACM Lite Map (This will return your U-Boat position marker)
Using the rings that slide over the scope might be slightly different from plain OLC, I can't remember the differences exactly (if any), but here is a link to some instructions from the Mod's author.
http://www.subsim.com/radioroom/show...&postcount=191
edit: Sorry! I didn't read your last post properly. I suppose you are using an earlier version of OLC which works with stock, I'm afraid I'm not familiar with it. The mods I mentioned above require the GWX3 supermod, and will not work properly (if at all) with just a vanilla install.
Perhaps this is why you had problems installing the other GUI mods you mentioned? You could try re-reading any documentation that came with those mods, and browse their threads in the forum's mod section to check their compatability with stock.
Rather than delete this post I'll leave it up as a suggestion just in case you ever decide to try GWX3. If you have never heard of it, then you can visit their website to find out more, or just browse their thread in the forum's mod section.
http://www.thegreywolves.com/gwx3/