We removed the top of the dorad and you see the bottom area. There are four holes in the bowl of the dorad. If water comes into the air scoop it will collect here and then drain down to the flat part of the dorad. There is a black rubber ring around the flat part and inside of that there is a high tube of plastic so the water can not get down into the boat or hose in our case. If a big wave came into the air scoop the water would push down the bowl and it would seal on the rubber black ring to keep out the big amount of water from entering the boat. The bowl is on a spring. From inside the boat (if the dorad is not connected to a hose) you can close the dorad by pulling down the bowl onto the black rubber ring.
Here we originally used the Drummel tool to cut away the flange deep enough for the new dorad base to fit in. However, unlike the starboard side, the old flange did not keep the hose secured in the hole. It keeps falling out into the cabinet below.
purchased from Home Depot in Mazatlán..
and the cut I did was not exactly straight.
from under the dorad bottom in the dorad scupper.