Hi Crematory.
You'll need to open the Menu Editor. If you check out the sticky above on Modding it shows how to do this if you haven't figured out that part yet.
Once open you can see a list of Pages, each page is bacically a different screen is SH5.
Eg: the (Page attack Periscope) is the page you see on screen when you click on the periscope in the conning tower.
You need to fing the Page for the gun you want to edit. I think there Page 20mm gun and Page 37mm gun. Once here you should be able to find the offending article and move it to another position.
I released a tutorial on using the Menu Editor here that may be of help:
http://www.subsim.com/radioroom/showthread.php?t=165968
Good Luck