What does the night time hand signal with a swimmer's lighting device on, raised arm, palm open, and fingers extended mean?

The nighttime hand signal with a swimmer's lighting device on, along with a raised arm, palm open, and fingers extended, is universally recognized as a way of indicating that the swimmer is alright. This gesture effectively communicates to others in the vicinity that the swimmer is in a stable condition and does not require assistance. The open palm and extended fingers serve to provide a clear and visible signal, especially in low-light situations, ensuring that rescuers or fellow swimmers can easily recognize it.

While there are various signals used to convey distress or requests for help, the specific configuration of having the lighting device on, combined with the raised arm and open hand, distinctly conveys reassurance rather than a call for aid. Other options would typically involve different signals that indicate varying levels of need or situations; for instance, a signal for need assistance would usually be more frantic or less reassuring than the calm indication of being alright.