See also: below decks
belowdecks (not comparable)
- (nautical) Below the main deck of a ship.
2003, Edward T. O'Donnell, Ship Ablaze: The Tragedy of the Steamboat General Slocum, page 54:
- Lastly, Lundberg went belowdecks to inspect the boat's bulkheads and hull—for what, it was not clear, since he had absolutely no knowledge of steamboat design.