This sounds like a placebo, but hear the technical logic out. The original European Ship Simulator has a bug where the physics tick rate is tied to the DRM handshake. If the DRM server is slow (or if you're offline), the water simulation drops to 30Hz.
The official system requirements for European Ship Simulator are moderate but can still pose a challenge for players with lower-end hardware. Players may experience performance issues, such as low frame rates, long loading times, and even crashes, especially if their computer does not meet the recommended specifications.
: Once installed, the game files are typically bit-for-bit identical to the original scene release. Some users report that repacked versions run better because they lack the "bloat" of original DRM launchers, which can sometimes cause stuttering or compatibility issues.