On the bridge of the Estonian warship Sakala, a crew member out on patrol moves a camera, zooming in on a Panama-flagged oil tanker 300 metres away in the Gulf of Finland. The tanker, which left a Russian port bound for Egypt, is considered by maritime experts to be a member of Moscow's shadow fleet — often old tankers with opaque ownership that try to work around international sanctions. At a time when the eight NATO nations bordering the Baltic Sea are on high alert after a string of undersea power and internet cables were suspiciously severed, Russia's shadow fleet…