A system is disclosed for providing emergency buoyancy to a vessel in response to a flooding condition in one or more vessel compartments cause by external explosion, collision or projectile damage. The system may comprise one or more flexible inflatable bags disposed on an upper inboard bulkhead of one or more vessel compartments. When a flooding condition is detected in a compartment due to breach of the ship's hull, an integral gas delivery system may provide a quantity of gas to the interior of the bag in that compartment, causing the bag to expand and push flooding water back out through the ship's hull. This displacement of water, and the buoyant force provided by the filled bag will enable the ship to maintain nominal floatation. The system may be configured to provide a controlled expansion of the bag(s) to enable personnel located in the compartment sufficient time to evacuate.