Marines are not that useful on the standard map, but they truly shine on the rising tides map. If one one has ever noticed, almost every single one of the victory sites is near a coast, but does not have a direct port to it. I have taken many victory sites in this very manner. (And if someone uses this information to take a victory site from me one day, I will be very upset.)
Alle sagten: Das geht nicht. Dann kam einer, der wusste das nicht und hat es einfach gemacht.