Battery Box

I've read the specs. for Coast Guard requirements and still have a
question with regards to batteries.
The starting battery is in the engine compartment.
The engine is a gasoline engine.
I built a tray that the battery has to be lifted up to set it in. Has
a lip all the way around. 
The battery has only 1" of clearance on top of the battery. The
battery slides under the berth deck into this tray. It's really hard
to lift this battery up and out of the tray. I have a clamp that holds
the battery into the tray.
Question is, does the battery need to be in a box or is it OK to sit
it on a tray?
I worry about the side of the battery cracking and leaking the acid.
Dan