[starsailor]

There obviously has been a change between the later models.  My 4 A/C units discharge into a manifold that has three gravity drains connected to it also. The manifold is then connected to a single 2 1/2 inch overboard drain located on the Starboard side under the swim platform about 1 inch above the waterline.
The 2/1/2 overboard line clogged with barnacles and caused the pressurized water from the A/C units to back up into the gravity drain hoses connected to the manifold.  There are no check valves to prevent the water from being pushed back into the drain lines.  The pressurized water seeks the least path of resistance and is pushed back up through the day hatch drain, where most of it is just overflows onto the deck, however some of the raw water slips past the seal and into the engine room.

I am looking for the way Tiara solved this problem on later models.