Help, yes. Prevent, who knows? It's not ideal but, for a single drag point configuration, it might be better than having the drogue surging forward in the face of a larger sea a couple crests astern and slackening the rope when the boat is plunging down a steep wave face.Hmmm, is that a good thing? What happens if the boat and anchor are both in a wave trough? Will the anchor help prevent a broach?
It would have to be a pretty large drogue though. The Jordan swept cone area for my size boat would be equal to a 4' - 3" diameter sea anchor. The single cone is going to work fine most of the time but, when the waves get in just the right sync, the boat is going to broach, accelerate and put a sudden strain on the line, or frequently put a much larger strain on it than the Jordan. Its value is covering the maybe 5% of the time when your boat is in danger even with a single drogue out. A lot of wave combinations will go by in a storm and 5% can be a lot if it's the 5% when you roll your boat.