what it is...is
a cover, either, fabric (usually sunbrella), fiberglass or metal with forward and side windows mounted on the coach roof and covering the companionway opening just aft of the coach roof into the cockpit area. what it amounts to is the equivalent of a windshield on a power boat or a car. Basically it will keep spray and splashed water coming over the weather side of the boat while under sail or under power and driving into or abeam of the waves. It is often a stand alone unit but it can be combined with a bimini, side curtains, center fly and aft curtains to enclose the cockpit. You can spend a little money on one, relatively speaking or a great deal depending on the material used and how total a cover you need/want for the cockpit.For example: Island Nautical has ready made ones for most boat makes and they run about a thousand bucks complete with frame. These are self-installed kits. Or you can go to a custom builder and spend a lot more and have him install it professionally. Go out to the marinas this summer and look around at the various options and talk to the owners. Most will give you the "scoop" on the equipment they have and how well they like it or don't like it.Happy Hunting,Mike