http://www.brayyachtdesign.bc.ca/article_twinkeels.html
In summary, this article describes boats with what are called twin bilge keels, which come off the hull like a shark's lower fins. When the boat heels, the leeward keel goes vertical in the water while the windward keel goes horizontal.
According to the article, this results in numerous efficiencies.
On a Mac:
--They could be setup such that the keels go over the trailer tires out to the 8' limit. Goat posts on the trailer would have to be moved forward of the keels.
--They could be permanently ballasted if you don't mind the increase in tow weight of about 500lbs. This would make the Mac far less tender. The windward keel ballast would become more effective due to leverage as it comes up in the water, meaning that you could have less ballast weight overall. My initial calculations show that two 250 lb. bulbs at the bottom of two 2 ft. keels would be equally effective as the water ballast.This presumes a 60 angle on the windward keel with 5 feet from the bulb to the center of buoyancy, which is essentially the distance from the bulb to the centerline.
--Planing would not be possible. The keels would make a planing hull unstable. The only reasonable solution here would be to hinge them so they could be raised vertically to get them out of the water, or to do this on a Mac with a displacement hull such as a 26D (which would be the right hull to mod for this IMHO).
--They ground completely flat.
and 
boats don't have an issue with this, but most sailboats do.Anyway, thought it was a very simple solution and I'm surprised I don't see a lot more of this. IOR rules forbid them apparently.
(As if you needed any help dreaming your dream).
maybe even add small wings to them not sure if that would be an anvantage though "wings" that is 
