For a new tank, here is a good drawing from Sparkman & Stephens.
Yacht Design - Type Plans
The USN version of this fill uses more holes in the stand pipe , and a very fine screen that lifts for cleaning with the stand pipe. Our method is to use an 8 inch deck plate with the fill under ,for extra protection from standing wateron deck
The site itself has hundreds of really fine mechanical drawings of proper instalations for many boat questions.