Herring is a light missile boat that can fire at surface and air targets. Less a scout than the Supporter, it fills a harassment & spotting role with its long sight and firing range. They outrange torpedo launchers, and harass expanding constructors very well.

Their AA firepower suffers vs. serious aerial attacks, but effectively protects your early fleets from EMP drones and gunships.

They are hopeless vs. direct combat ships like Dolphins, and submarines. Never over-build these.

Until you have Oppressors, Herrings can effectively destroy inland metal extractors and other infrastructure with their range.