The frigate HMS Sutherland was on hand when a landing craft of the Royal Logistics Corps got into trouble in rough weather off Portland in midweek. A freak wave had torn her landing ramp free, injuring two of the three-man crew. Water was pouring inboard and it seemed highly likely that she would founder. Sutherland, exercising off Portland at the time, sprinted to the scene and as the two casualties were lifted to safety by helicopter, dispatched a seaboat, complete with repair crew, to the scene. Led by the experienced Petty Officer “Brum” Tuite, this boarded the stricken craft, and winched the ramp back up, enabling the water to be pumped out. With the situation stabilised the landing craft was then escorted to port.Here's a picture of the landing craft in action:
So as well organized as the Royal Navy, they are not immune to freaque waves by any means. We don't know how often this kind of things happen, probably along the similar frequencies as in the civilian world. I doubt the military would like to publicized this kind of things. But freaque waves are certainly by no means discriminatory.