between decks
'tween decks

Okay, he had an idea how far it was between decks.

A simple switch of the patch from one eye to the other might have saved time when going between decks.

When they came to the first subsidiary connection between decks, it was clearly enough marked.

The warren was between broken decks, out of a man's reach.

"You should be able to wedge the Falcon between decks here."

This boy is ill and should not be down here between decks.

In a large vessel it is a permanent ladder between decks.

To understand this, one must first examine the difference between decks and porches.

She paused, between decks, and gave him a minatory look.

One example might be a speaking tube used aboard ships for communication between decks.