Also floating on your back is a great way to rest and regroup. One thing that could be challenging with it is that if the waves are too choppy or with strong wind, it may be hard to keep the face esp. nose clear of water, which could add to panic. This position also needs some light kicks to keep legs from sinking. Restoring the breathing rhythm is what lets one get some control over the situation.

No matter the skill, we humans are still the land creatures. Let's stay safe!