Why are small fishing vessels more vulnerable to capsizing than large ships?

Small fishing vessels are significantly more vulnerable to capsizing than large ships because they are more susceptible to large upsetting moments during routine operations, such as lifting heavy nets over the side while being rolled by heavy seas.1

In naval architecture, a vessel's stability depends on the relationship between its centre of gravity ($G$) and its metacentre ($M$). Stability is maintained when $M$ is above $G$; if $G$ rises above $M$, the vessel becomes unstable and capsizes. Small craft are particularly prone to this because environmental factors, such as ice accumulating on upper structures, can significantly raise the centre of gravity, making the vessel top-heavy and difficult to stabilize at sea.234

Furthermore, while large ships are rarely at risk of capsizing without hull damage, smaller vessels face dynamic hazards—such as wind gusts or sudden shifts in load—that can easily overcome their limited capacity to resist rotation. Safety standards for these vessels are complex, as they must account for the high variability in size and operational conditions managed by the International Maritime Organization.1