The mod is
WSM 3.0, which is fantastic by the way.
I have quite a few other mods installed and plenty of custom tweaks to art and sound. I didn't mess with the ship's strength and armament. I guess I just took advantage of the right conditions. I was surprised to see my boat survive when the water all around me was exploding. I guess GWX did a great job of removing the laser guidance for the guns. I only hit them because my gun crew is fully decorated, experienced, and promoted.
I also use a few tricks. I take full advantage of my destroyer's slender shape by running very nearly straight for my oponent with just enough angle to get the rear guns in line for a shot. I keep a standing order to hold fire until all guns are aimed and I am as close as I dare under cover of dark/fog/weather and then open fire with all guns in an old fashion broadsides attack. I occasionally man the main guns myself if my crew seems too inept for the task.
It also helps more than you'd think to fire your machine guns at them manually, although aiming can take some practice. I have found that the quad AA, and even more so the double heavy flak with exploding AA shells do wonders for removing unnecessary items from their deck. They seemed oddly inadequite for removing the Hood's guns though. hmm....
I got close enough to make the first shot manually and remove key parts of the ship on a few occasions. They have a hard time firing at you after you remove their main guns or fire control towers.