I think they serve somewhat different functions. A drogue, deployed from the stern, is intended to slow a boat while sailing/running downwind and to prevent a broach / roll situation from developing when a large following sea engulfs the boat. A parachute 'anchor', deployed from the bow, is more of a way to "stop" the boat at sea during a storm. The Pardeys have written quite a bit on the subject. Their strategy in the use of the para-anchor involves heaving to, deploying the para-anchor, and then letting the boat drift very slowly downwind and, in the process, creating a 'slick' to windward of the boat that disturbs the surface tension of the water and inhibits the wave from breaking over the boat. The para-anchor is probably much harder to deploy and recover, but set correctly, it apparently allows you to retire below and get some rest. With a drogue deployed I think the boat has to be actively helmed.
I have a sea anchor and hope never to use it! I also have a drogue. Ditto.
Last edited by billyruffn; 02-20-2008 at 08:48 PM.