There is no tide and the water is generally choppy. According to the weather there can be waves up to 1-2 meters but its generally not so. There are also many days where the water is also calm and flat, but only in light wind days.
Directly in Roving and around there are no sandy beaches. Mostly small stones and rocks. Hard sand next to shore. You can forget self-launching of kites.
Rovinj is a nice town to wine and dine. Old architecture and nice restaurants. There are a few bars and very little clubs. After a certain time at night the nightlife is dead. Perfect place to spend a 2 days or so with your partner.