SOURCE: AFI
The recent capsizing of INS Brahmaputra in harbor has prompted the Indian Navy to convene a Board of Inquiry (BoI) to investigate the incident. While the BoI’s findings will take time, here is an analysis from a fire fighting and damage control specialist’s perspective on what could have potentially gone wrong.
A ship undergoing refit is at a higher risk of fire due to many of its systems being under repair. This period is marked by “Hot Work” activities such as welding and gas cutting occurring at multiple locations onboard, which increases the likelihood of fires. Although common, such fires can be effectively managed with prompt action and appropriate fire extinguishers. Problems arise when these conditions are not met, allowing fires to grow uncontrollably.
When fires escalate, water is typically used to extinguish them, with sea water being a common choice due to its abundance. However, the water used in firefighting often accumulates on the ship’s deck, adding to the vessel’s weight and impacting its stability. To maintain stability, the excess water must be pumped out. If the ship’s pumping capacity is insufficient—either due to design limitations or systems being under refit—stability issues ensue. Water accumulating more on one side can cause the ship to develop a list or heel.
A ship’s stability relies on the balance between its center of gravity (CoG) and center of buoyancy (CoB). When the ship is upright, these points are aligned along the centerline, with the CoG below the CoB. As more water accumulates, the top weight increases, moving the CoG upwards. Concurrently, a developing list shifts the CoB outwards and lowers it, creating a righting arm that accentuates the list. If the CoG rises above the CoB, the ship loses buoyancy and capsizes.
Visual evidence from the incident shows a fire blazing in the superstructure, indicating that water added to the top weight. Further footage depicts the ship with a dangerous list to port, reinforcing the theory of water accumulation impacting stability. This incident is notably the second of its kind for a Brahmaputra-class frigate, following a similar occurrence with INS Betwa in December 2016 during undocking in Mumbai.
Repeated incidents with the Brahmaputra-class frigates may raise questions about the design stability of these vessels. It is important to note that warship design often involves a trade-off, sacrificing some stability to enhance agility. The BoI will undoubtedly examine this aspect and recommend corrective measures if necessary.
Despite the capsizing, this is unlikely the end for INS Brahmaputra. Drawing parallels with INS Betwa, which returned to operational status after its incident, INS Brahmaputra is expected to be back in fighting condition within a few months. Best wishes are extended to the Indian Navy and the INS Brahmaputra team as they navigate through this challenging time.