The Navy is almost never mentioned compared to the Army and Marines where I'm from.
Yea the navy or maritime force isnt much up for discussion or popularity even though sea based war is so big
Agreed, maritime war is so big yet it is really under exaggerated at times. 
Yep the navy is a branch of the armed forces and used for naval battle but isnt much of a thing
So what makes them so different? Do they just train for sea combat and train to use boats instead of other equipment?
The entire strategic point of the navy is to protect the borders and shores of a country
That makes sense, since all borders eventually end up at some form of water, at least continental wise.
Yep the strategic defense of the navy is a big part of it