If the bottom of the duct is parallell to the keel and the hull is moving with the bow 5 degrees \ up that puts the front of duct at a 5 degrees \ up too. That would mean that the duct is plowing water. Thus creating a void on the backside between the duct and the keel. I understand that it would create lift at that point. But wouldn't that also be taking water away from loading into the suction?