[PA Engineer]

I think that is the designation for a guided missile cruiser.

[BushMeister]

Rogue waves in the Mediterranean are relatively unusual. They usually occur in the open ocean, often near the tip of South Africa, or in the southern seas. Underlying water current flowing in the opposite direction to surface waves seems to contribute to rogue wave formation.

Here's an article claiming that in this incident, windows on the 5th deck of the ship were broken, resulting in the fatalities and flooding:

USAtoday

Pic of the ship: