see the attached figure to better understand the problem
we know that
in the triangle ABC
tan 48°=AB/AC--------> AC=AB/tan48°------> 1200/tan 48°------> 1080.48 ft
in the triangle ABD
tan 33°=AB/AD---------> AD=AB/tan 33°-----> 1200/tan 33°------> 1847.88 ft
the distance between the ships is AD-AC---> 1847.88-1080.48----> 767.4 ft
the answer is
the distance between the ships is 767.4 ft