Looking thru at techs today I discovered that weapons take more space on Huge ships than on tiny ships.
That is a nano ripper may take 5 space on a tiny and 9 on a huge ship. (I don't recall actual numbers but it was something on the order of that.) Other weapons behaved the same. This looks very much like a bug to me and if it's not info on actual ship sizes would sure be helpful! One space should be one space.