I’d probably approach it a bit differently. Instead of relying on volumetric scatter for the background, try separating the environment into layers.
Use an HDRI or sky texture for the lighting and reflections, then add atmospheric depth with a light volume or mist pass rather than making the volume do all the work. The sea reflection will generally come from what’s actually visible to the reflection rays, so if the sky is mostly being created by volumetrics, the water often won’t reflect it the way you’d expect.
Another thing to check is the water shader’s roughness and whether the reflection rays are actually seeing the background. If you’re compositing the ship later, you may also want to render a separate reflection pass or use Cryptomatte to blend everything more naturally.
If you can share a render or your node setup, it’ll be much easier to pinpoint why the sky gradient and reflections aren’t behaving as expected.
