[JimRed]

Many ships have Marine guards assigned to them.

No Marines, no nukes. Marines, maybe nukes. or, so I've heard.

[RaceBannon]

Marines are on ships as other than nukes, some carriers have Marine Squadrons, too.

Plus, not every ship that has Nukes has Marines. Subs dont carry Marines...but subs aren’t ships, then, are they! :)