OK, how about this?
I've only seen it once, but the item under the companionway step sounds like the air vent for a ballast tank. If so, what you have is a Hunter 23.5, not an H23. Here are a couple of easy clues to help you identify your boat:If it has a fixed wing keel, straight blue stripes along the hull, side decks, a small but deep cockpit and a wooden tiller, it's most likely a Hunter 23. However, if you have a retractable keel, multi-color free-form "splashes" along the hull, no side decks, a wide but shallow cockpit and an aluminum tiller you probably have a H23.5. Sales brochure pictures of both boats are in the "Boat Specs and Photos" page here on HOW. If you have an H23.5, the "drain" is actually the air-vent to the water ballast tank.Hunter uses water ballast in its newer trailerable boats to increase stability without forcing you buy a big SUV to haul an extra 1000 lb around on the trailer. The ballast tank is under the cabin floor. It has a port below the waterline of the boat and the aforementioned air vent up top.When you first put the boat in the water, opening the air vent allows water to enter the ballast tank through the underwater port. The tank will not fill otherwise. When the tank is full, close the air vent and sail away.When you are ready to put the boat back on the trailer, open the air vent again. As the boat comes up out of the water, the water in the tank drains out. By the time you are ready to drive off, the tank should be about empty. Lord, I hope I'm right.PeterH23 "Raven"