Over the years we have noted that most conventional ships do not have the redundancy as required in the Offshore Ship industry. Ships working in the Offshore industry, from Dive Support, Drilling, Accommodation to PSV etc require at minimum Class 2 FMEA capability.
This level of detailed study gives the owner, crew and client a comfort that during construction the design and testing has proved that the ship is capable of withstanding a single point failure without the loss of control or position.
Every seagoing ship should be designed to as a minimum Class 2 FMEA, ensuring that the ship has been designed and proven to be capable of absorbing a ‘Single Point Failure’ without the loss of position or control and allowing the ship to recover to a point of safety. The ship should also have annual trials during which testing will show that the ship continues to meet the required redundancy capabilities and all systems are fully functional.
The annual testing also allows the ships crew to show they are familiar with the systems under their control and also show the required responses during a test failure condition.
Most seagoing ships do not carry out this type of testing, which means that crew are not familiar with the type of failures that may occur and how they should respond to them.
The incident of the container ship DALI (https://www.bbc.co.uk/iplayer/episode/m0025pbd/why-why-bridges-collapse-the-baltimore-disaster). This is a clear example of failure/blackout etc, in which an FMEA may have mitigated the incident to at worst, loss of a single propulsion system and failure of one half of a switchboard.
As an overview of Failure Modes and Effects Analysis (FMEA), the FMEA for ships is based on a structured approach to identifying potential failure modes of various systems on board, determining their effects on the overall system, and assessing their severity, likelihood, and ability to detect the failure before it leads to a disaster.
FMEA is a tool used for identifying risks, improving system reliability, and ensuring safety. Below is an overview of an FMEA process that should be applied to various ship systems.
Before conducting an FMEA, it is important to identify and break down the ship into various subsystems that could potentially fail creating a worstcase failure (WCF). Typical ship systems include:
- Propulsion System
- Engines (main and auxiliary)
- Gearbox
- Shafting (preferably duplex on all oceangoing ships for redundancy)
- Rudder and steering system (duplex where required)
- Electrical System
- Power generation and distribution (switchboards, split)
- Batteries and UPS systems
- Emergency backup systems
- Water and Fuel Systems
- Freshwater and Seawater Cooling systems (separation for redundancy)
- Fuel management and filtration systems (separation for redundancy)
Steps in FMEA for Ship Systems
Identify the Components and Systems
Each of the systems above is further broken down into individual components or subcomponents. For example, for the propulsion system, components would include the main engine, fuel system, exhaust, cooling system, and so on.
Identify Possible Failure Modes
A failure mode is any way in which a component or system could fail to perform its intended function. Some examples:
- Main Engine: Loss of power, overheating, fuel contamination
- Fuel System: Fuel leakage, contamination, clogged filters
- Rudder/Steering: Loss of steering control, damage to rudder
- Electrical System: Power failure, switchboard separation, wiring fault, generator failure
Assess the Effects of Each Failure Mode
Once potential failure modes are identified, there is a need to analyze their effects on the ship. This includes direct and indirect consequences for safety, performance, and operational continuity.
For example:
- Loss of Main Engine Power:
- Effects: Loss of propulsion, risk of collision, stranded at sea.
- Fuel Contamination:
- Effects: Engine failure, shutdown of auxiliary systems, damage to engines.
- Steering Loss:
- Effects: Inability to control the vessel’s direction, navigation risks, collision risk.
Determine Corrective Actions
Once the failure modes are ranked, the next step is to develop corrective actions. Some of the common measures include:
- Preventive Maintenance: Regular inspection and maintenance procedures to avoid common failure modes.
- Redundancy: Implementing backup systems (e.g., additional fuel systems, secondary propulsion).
- Training: Ensuring crew is trained to handle failures effectively and quickly.
- Design Modifications: Updating systems or components to improve reliability.
- Safety Systems: Introducing new or upgrading existing safety equipment.
Key Recommendations for Ship Safety
- Preventive Maintenance: Routine inspections and maintenance schedules should be implemented for critical systems.
- Redundancy Systems: Backup systems (e.g., auxiliary engines, emergency power) should be in place for vital functions.
- Training and Drills: Regular crew training on emergency procedures for failures.
- Monitoring and Sensors: Use real-time monitoring systems to detect failures early and prevent accidents.
- Safety Protocols: Clear safety protocols in place for all systems and emergency situations.
Conclusion
FMEA is a systematic approach to identifying and mitigating risks on board ships. By identifying potential failure modes across different systems and components, assessing their effects, and implementing corrective actions, the overall safety, reliability, and performance of the vessel can be significantly improved. This proactive risk management method reduces the likelihood of critical failures and enhances safety on board ships.
Opinion.
All ships should have an FMEA Class 2 as a minimum, Yes there is a cost involved but safety outweighs cost and as has been proven not just on the Baltimore bridge incident but on numerous incidents the impact of small extra cost to a ship design and construction at the beginning is minimal in comparison to the cost of human life, failing commerce in the event of an incident and of course the financial cost for insurance in the long run to ship owners and insurance companies.