Some sort of Fog Horn. Ship or Locomotive I would guess.

VINTAG SHIP SAILBOAT BOAT HAND PUMP OPERATED FOG HORN | eBay

SHIPS FOG HORN FROM NAVY SHIP. VERY VERY OLD. POSSIBLY OVER 100 YEARS OLD! GREAT | eBay

HUGE VINTAGE IBUKI JAPAN AIR HORN SHIP TRAIN LOCOMOTIVE WHISTLE SIREN | eBay