Also partially crosses over. A PAV isn't strictly limited to a system. It can patrol independently for a period of time (possibly as long as 3-6 months) and/or travel with a fleet. A SDB generally won't leave the confines of a system or the immediate vicinity thereof.
The Risal-class starship straddles the divide between heavy scout and light destroyer, filling either role as needed. Named for a variety of Andorian fighting knife, Risals are popular with Andorian officers in the so-called "Blue Fleet", but less so with those of other races, as the crew accommodations are somewhat cramped for those not used to living in close quarters with many individuals for long periods of time.
The Lal-Tanaah-class destroyer escort is another class popular with the Andorian officers that make up the bulk of the "Blue Fleet". Solid engineering backed by the firepower of a 4-tube heavy torpedo primary armament system allows the class to excel in the escort and perimeter defense/patrol roles. The addition of the highly sensitive Aracebo-1707 sensor pod in the Mark II configuration further enhances the already impressive search and detection capabilities of this class. The class is named for those who made a profession out of guiding and protecting ancient Andorian trading parties as they made their way from city to city, a job that required a strong sword arm and keen senses. The word "lal-tannah" in Andorian literally means "outrider", though some also translate it in context as "ranger".