Hull weights for a strong ship

I will be interested to compare what I think should be adequate hull weights for ships compared to what Springsharp "thinks". My position is that ships with a moderate girder length (less than 15) should be able to use a hull weight of Length x Beam x Hull Depth x 3.0 x 10^-3, and that should do the job. By my calculations, the Queen Elizabeth class battleships had factors of about 2.85 x 10^-3, which would have given a lighter structure. I assumed that was acceptable due to the small girder length for the hull depth.