It sounds like you are new to boating and new to this boat. The statement "last night all "heck' broke out in the aft cabin" I am assuming did not involve persons or animals cavorting.
With those assumptions, my first recommendation is to start at either the bow (front) or stern (back) of the boat and open every cupboard, door, and hatch taking pictures and exploring everything inside all of the voids so you know what is there. If it is something mechanical, turn it on and watch it operate. If it fails to work as you expect take pictures and make note of what you see, hear and smell. Once you have all of this new information start to categorize it as to what it does, how it worked, and why it is on the boat.
Only by knowing what is there and how it works can you possibly be able to understand what is happening to your boat when you hear a strange sound or smell a bad smell.
Once when sleeping on my boat there was a tremendous ruckus going on. I thought it might be in the V-berth. No it was on the bow above the V-berth. To ducks were cavorting leaving their feathers and a mess on the bow when I leaped out of the cabin with my flashlight.
Duck Coitus Interruptus.