Rainbows may also form in the spray created (called hullbows).
The light is first refracted as it enters the surface of the hull, reflected off the back of the tail, and again refracted as it leaves the most convex arena of stoke. The overall effect is that the incoming water is reflected back over a wide range of angles, at an angle of 40°–42°. The angle is independent of the size of the hull, but does depend on its refractive index. Seawater has a higher refractive index than rain water, so the radius of a 'hullbow' in sea spray is smaller than a true rainbow. This is visible to the naked eye by a misalignment of these bows.