Bulkheads were partitions separating cargo from crew on ships — and the Titanic's fatally short bulkheads changed maritime safety law forever.
A dividing wall or partition within a ship, aircraft, or building, especially one designed to resist pressure or prevent the spread of fire or flooding.
From bulk (a framework, stall, or projecting structure, from Old Norse búlki, cargo) + head (front, partition). Originally a partition in a ship separating cargo (bulk) from other sections Key roots: búlki (Old Norse: "cargo, freight"), head (Old English: "front part, partition, end").
The Titanic's bulkheads were designed to keep the ship afloat even if four compartments flooded — but the iceberg ruptured five. The bulkheads did not extend to the full height of the hull, so water spilled over the top of each bulkhead into the next compartment in a cascading failure. This disaster led to the International Convention for the Safety of Life at Sea