Level 3 or 4 or nuclear yes. But only ships and sea transporters, never submarines. Have a look at the units Info >> either in the research menu >> select any unit and then click on the right side the small "i"nfosymbol >> or select any unit / army on the map and then click the small unit picture.
And, same as on land, and as Kanaris wrote, rockets can not track moving units, they hit there, where the target unit was when the rocket was launched.
Normal rockets have only a small "damage spread" of about 5km. Depending on the flight time of the rocket, a moving unit may "flee" from the target area. However, nuclear missiles (and also all nuclear bombers) have a damage radius of 50km.
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- more or less cleverly camouflaged as a real game sometimes.
So beware of caltrops, spring-guns and booby traps.
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