Military Adjacency Bonus

In general I am a little bit confused about shipbuilding.  I understand  my shipyard gets some portion of my manufacturing but what proportion is it?

I liked what someone else on this forum suggested which was to add a "slider" almost like the tax bar which allocates manufacturing between social and ship building.

But putting the above point aside, some planet improvements claim +1 military.  I have not seen any military production buildings as the Terrans (at least in the first 50-75 turns).  Are there buildings which produce ship building production only?  GalCiv3 had some early game improvements for planets which did this.

Disclosure:  I could very well be missing some obvious component here.

 

The game has been very addicting, keep up the good work!