If I'm inside water, is the amount of heat energy I can receive capped because water can't go above 100°C?

Question

I just learned about double-boiling, where instead of putting a pot directly on the flame stove (where it can get too hot), you put a big tub of water on the flame, and put the pot in the tub of water. The tub of water will stay at a constant 100°C, heating up the pot at a nice stable rate.

But this struck me as kind of odd. The flame can be a 1000°C degrees, but as long as I'm in that tub of water, the highest temperature I'll be feeling is 100°C. Assuming I was a super-human who could withstand 100°C (but not a 1000°C flame), wouldn't submerging myself in water literally make me impervious against flame or any strong heat source? Or am I missing something here? Like, even though the temperature around me will stay 100°C, I'll still have an insane amount of heat energy transferred to me?

Btw, please disregard the effect of insane heat causing things like plasma or fusion (like on the surface of the sun).

Answer 1

Yes, the boiling water in the outer boiler stays at a constant 100°C, assuming that the water in the tub can equalize its temperature. That's not usually an issue, since boiling water has a lot of motion, so the water is well mixed. There is some localised heating >100°C of water at the base of the boiler, but that gets quickly dispersed. At the base, bubbles of water vapour are created, and their temperature can be initially >100°C, but they quickly equalize temperature with the surrounding liquid water as they rise.

Of course, when using a double boiler, it's important to keep topping up the water in the outer boiler so that it doesn't boil dry.

So a superhuman in the pot is only protected if there's a source of water replacing the water that's getting boiled off.