The Captains Nemesis wrote:

Read some research recently...wish I could remember where...which
found that fluid from any source will combat dehydration.
That coffee and tea will not increase the risk at all.

I'll see if I can dig it up.

I'd be interested in seeing it.

FWIW the current wisdom on drinking caffienated drinks... in the short term, yes they
help with hydration. However, if you're considering a longer time frame than you can
hold your bladder (just for example, the physiology is not related) then you should
drink at least as much non-caffienated as well. Caffiene is a diuretic and will pull
water out of the body.

However falling asleep on watch is a bigger hazard than dehydration for most
people....

DSK