Battery set up on a Carver 355 , configuration

[carver battery]
I need some input on a Carver 355 '98. Battery configuration
This is my first summer using this boat and the previous owner nor the marina are able to give me any info on the battery configuration. It seems that the boat has been used by the previous owner strictly as a day excursion boat,and then a full time cottage while plugged in at the marina, with 4 televisions, satellite TV, air conditioning etc, and that ,extended unpowered overnight cruising was never the case.
This is what I have been dealing with in the bilge.
1 dedicated 12 vt. Battery for the generator
1 dedicated 12 vt battery for both engines
2 series 6 vt batteries for the house.


When I compare this to the Carver owner guide book which accompanies the boat, it seems that this is how it is, with no individual batteries for each engine.
The book goes on to explain that when running, charge both battery systems, and switch over ,to one or the other when not charging.

This is the issue.
After 2 days the starter battery is very low and the fridge is warm. The generator gets this charged up enough to restart the engines after about a 5 minute run. The interstiing thing is that ALL THE LIGHTS ON BOARD ARE BRIGHT

So, is it possible that fridge is hooked up to the motor batteries and not the house batteries.

I have checked the wires that connect to the starting battery, and I do not see any connection to the fridgidaire
Is it possible that this connection is done elsewhere in the system, and does anybody think that this was intentional, that the fridge is on the starting battery

PS. All of my other boats had a dedicated battery for each engine, and the house was independant of engine batteries.

PS. There is really no space to have added an extra battery




Elliott

Thank you so much for your response.
The previous owner told me he always left the switch on Both
I installed solar panels , so I also have left the switch on Both, so that charging at all times is both. I realize now that the solars do not go through the switch and that they are direct so in fact i could select position 1 or 2 without affecting charging.

But, in my posting I stated that the starting battery runs down as well as the fridge BUT not any of the lights, so this tells me that the fridge is not connected to the house, so, I am not sure if switching the cables would actually change anything other than reversing which batteries will drop down first,and, in either case the engines or fridge will be together.
It is the fridge lead which I think should be linked to where the lights are connected.
However , your input has better helped me to understand this boat.