24 hour dive

[markosis]

Imagine, if you must that someone has agreed in principle to taking on a 24 hour Open Circuit dive in the shallows of a UK inland site that'll have reasonably warm water. It'll be for charity.

Assuming the dive runs with support divers providing new cylinders and permanent buddy pairings for the 24 hourer, and that provision can be made to stop the diver from dying of Hhypothermia (I'm thinking heated vest thingy).

Would it be medically safe to do this?
I've had a think and so far the following things stand out:

Exhaustion / risk of falling asleep underwater.
Could be controlled with the use of a full face mask. But then the diver can't eat or drink. So dehydration and hunger would be a problem.

On regular regulators, that could be avoided, although there's the chance that the reg would fall out if the diver fell asleep. Would Manta mouthpeices help with that?

Immersion shock.
On exit of the water, would the diver stand a chance of suffering from this? Or is it only an issue when the bottom half but not the top of the body has been immersed in water?

Other issues.
Would deco be a problem? The dive would go no deeper than 10M, so it shouldn't be an issue, but it will be a long time. Nitrox might be useful in the long stretches of the night, but the diver would have to be qite wary of watching their Pulmonary loading.

Any thoughts on this would be greatly appreciated. Ta.

[chas49]

Already being discussed here:
24 hours underwater

[dilshan]

Was not aware of so many problems that can take place frankly speaking. I used to think that there are some people who enjoy their prolonged diving but later they are found to get so exhausted. Again these points should be made clear to all so that they learn to do this in the most effective way. Even the prevacid wont be of any help then.

[Harlequin]

Good luck with the venture but only one question...

Why in the UK when there are warmer waters to choose from...?