GM is right. And, I know of no ships with a pink lower hull. I have experimented with many reds, but I always return to a straight flat red for my American ships. I have grown up around the Navy my entire life, and I have seen many ships in drydock. Flat red is not perfect, but it comes the closest.
On an interesting note, there is a photo of a Ticonderoga class CG in drydock with a blue lower hull, though I have forgotten which ship.
Bill