I have a Tartan30 #256 and I have 2 deep cycle batteries in the well next to the engine. I have seen one installation
where they used a shorter battery and were able to get 3 in the well..
As far as the height of the battery there is a clearance problem so I figured out where the battery posts would be at and routed out the 1/2 in in the cover i needed to get a flush fit for the cover. There is also two 3 inch holes in the well that allows the bilge
blower to vent any battery fumes out of the well with the other fumes or gasses.
I have tried to think of what they might have used a battery in the stern forand there is any number of bad ideas.
I used those compartments for all manner of storage
and it the battery is not properly in a battery box
, and vented there is a good possibly of spark/fire/explosion.
It also just adds that much more weight to the stern which in conflict with one of the great things about the Tartan30 with the midship mount engine, batteries, and tanks
keeping the weight very low and in the middle of the boat. That's how I see it anyway.