[Dry Foot-Wet Foot]

This is a 31` Open.
The return seems to be behind the steps entering the cabin.
There is no indication that anything here is easily removable or designed for access.
This area is the opposing side of the engine room bulkhead, so it doesn't seem a likely nor roomy enough place for the A/C unit to be mounted.
I'm thinking the unit is mounted somewhere else and ducted over to the bulkhead.