A Step Change: From Historical RAOs to Live Vessel Motion Measurements
By Sahil Kochhar, Commercial Manager, Miros
Monitoring, understanding, and responding to vessel motion are essential for maintaining safety, efficiency, and uptime in offshore operations, whether in offshore energy or marine construction.
Over many decades, the consequences of neglecting this vital aspect of seafaring have become apparent. Ensuring stability, safety, and predictability in vessel motion is key to operational excellence.
Traditional Approach: Response Amplitude Operators (RAOs)
Vessel motion has traditionally been understood through Response Amplitude Operators (RAOs), which are pre-calculated models estimating how a vessel responds to various wave frequencies and headings. These mathematical functions are based on simulations or scaled model tests and have long been fundamental in offshore engineering.
Limitations of RAOs
Although RAOs remain a valuable tool, their limitations have become clearer in modern offshore settings. By design, RAOs offer static representations of dynamic conditions. They rely on assumptions concerning ballast, cargo load, and sea states, which means they often fail to capture the constantly changing realities of vessel operations.
“RAOs are, by nature, static representations of dynamic conditions, built on assumptions about ballast, cargo load and sea states, and as such can often fail to reflect the ever-changing reality of vessel operations.”
Live vessel motion measurements provide a more accurate and real-time insight into how vessels behave amid actual sea conditions, offering improved operational decision-making.
Author's Summary
This article highlights the evolution from static RAO models to dynamic live measurements, emphasizing the need for real-time data in today’s offshore operations to ensure safety and efficiency.