I am including a pic that shows the underside of the icebox. The picture was taken through the inspection port. There is room to drain into the inner hull/bilge area. The clearance to the bottom of the hull is about 1.5 inches below the fg foam insulation under the ice box. Be real careful if you use a power drill. Try to use a collar stop if you must, but better yet use a hand operated gear drill. (I have thought of this myself) It may be wiser to drill the hole sideways into the cockpit area, so that it drains into the sole gutter then to the footwell at the back. I have also thought of installing a guzzler hand pump against the inside of the transom, since the self draining plug is often not working as it was designed at the back of the hull. (but that's a different project)
The tubing that you see in the picture allows water to move from one side of the stringer to the other. It has nothing to do with the ice chest.
If water drained into the bilge area from the cooler, there is also the chance that cooler contents, coke, beer, banana mush, sandwich parts, etc would drain into the bilge where they may smell, grow, and otherwise be difficult to clean. Certainly there is a risk that they could plug up the drainage. Then on the other hand I sometimes think the original design with no drains, is pretty good, because other than sponging it out occasionally, it is pretty maintenance free.
http://groups.msn.com/RogerConrad/shoeb ... hotoID=105