Of all the regular denizens of our day hatches, one has a special place on our gear list: the cag.
The cags we carry are lightweight, hooded garments with a bungee hem that can sretch to fit over a cockpit coaming. We've only used them once on the water when a student seemed to be getting hypothermic, but we frequently pull them out on land and often put them on people who are getting cold and miserable. They fit everybody and have room for everything they might be wearing, including a PFD.
The effect is immediate, thanks to the combination of windbreaking and solar heating (particularly with our black one).
We could go on and on about how much we love our cags, but we don't want to be anoraks.