Possibly aiming down at 30 degree?
No way. The deck of the fantail on a Arliegh Burke DDG (Flight IIA) is about 15 ft above the water line. No way was there a 30 degree angle.
click here for photo
As for actual tactics involved, there isnt a whole lot involved other than positioning on the fantail of the DDG and waiting for clearnace to get a clean shot off.