The teenager only had a few days worth of supplies and survived by catching fish, burning wood from his hut to cook them, and sipping seawater through his clothes to minimize his salt intake.I've heard of drinking water through cloth to remove particulates, but I can't see how it could possibly lower the salt content of seawater. Other reports indicate that he did capture some rainwater, and maybe the flesh of any fish he could catch would be less hypertonic than seawater (?). But he did survive 49 days adrift.
30 September 2018
"Sipping seawater through clothing"
Most of you have probably heard the story of the Indonesia teenager who survived on a fishing raft adrift in the ocean for 49 days. This is the part that interested me:
Wet a piece of cloth in seawater by pouring the seawater over the cloth. Let it dry in the sun. You will feel a slight but noticeable stiffness in the cloth, like it's been very lightly starched. That's salt that the fabric has captured. It had never occurred to me that it might hold enough salt to make the dripwater potable, but maybe thru several layers, or multiple passes?
ReplyDeleteUnderstood. But as described the water would have evaporated, not percolated through the cloth. If the kid had a plastic bag to capture and collect the evaporated moisture, I could see a mechanism.
DeleteI hate to deny the possibility out of hand, since the boy and his people have a tradition of living from the sea.
I have heard that sea water enemas are the way to go. The colon will absorb water but reject the salt. There are several survival stories to support this.
ReplyDeleteAn interesting thought. With a quick Google I found this BMJ article on electrolyte transport in the colon -
Deletehttps://gut.bmj.com/content/43/2/294
This series of opinions and anecdotes -
https://boards.straightdope.com/sdmb/showthread.php?t=594096
And this article directly addressing the question with a negative opinion
https://www.thenakedscientists.com/articles/questions/would-sea-water-enema-help-hydration
I suspect a translation error. Certainly wearing salt-dunked clothing helps preserve body water, since it provides non-sweat cooling and prevents sunburn. Fish flesh certainly can provide water as well. But I at least see no mechanism for fabric filtering an ionic compound out of solution in a casual setting like this one. If there is such a mechanism, makers of desalination plants should be informed.
ReplyDeleteI agree with you. The cloth shouldn't filter dissolved ionic solids however several of the strategies employed (particularly consuming a small amount of sea water initially to fend off dehydration before switching to fishing and rainwater when available as a source of moisture) remind me of those recommended by Alain Bombard. I first became aware of him in this Futility Closet episode which I recommend.
ReplyDeleteI think the key to his survival was the sipping of small amounts of seawater. The human body can tolerate remarkable levels of hypernatremia (normal serum levels 140 mEq/L and survival is reported with levels over 200). But those extreme levels have to be reached slowly so there is time for salt to equilibrate across cell membranes.
DeleteIf he had taken in no saltwater and gotten volume depleted from sweating and insensible loss, he would have been worse off in terms of cardiac output and functional capacity.
The dangers of osmosis, like drinking distilled water and very saline water are likely overstated, by way of constant instructional repetition. Similar to the likelihood of getting pregnant through unprotected intercourse, or the dangers of cannabis. We might only know the "Reefer Madness" version of salt-water drinking.
ReplyDeleteIt would take some time before organs fail. You can eat a couple of teaspoons of salt and not die although it would equal liters of salt water consumed.
He may have drunk salt water through his clothes, when he had no access to rain or condensation, and it did nothing to change the salt content, but didn't kill that teenager instantly either.