Monday, June 25, 2012

Primordial soup

Nothing makes me more nervous than the typical boat's water system. Visions of explosive lumbo trickitis emanating from the lower blowhole, coupled with world class cramps or worse has generally discouraged even my most trivial usage of boat water. I would use it to wash dishes, or take a shower only if there was enough chlorine in it to bleach your hair Jean Harlow white, and sear your nasal cavities. In general, if you haven't make a serious investment in filters, disinfecting systems, and chemicals I think it should never be used for drinking. I know it's an audacious thing to say about your boat's expensive water system, but I think it's the truth. Just look at all the news stories about near death experiences, and severe illness boaters have had after drinking boat water. What? There really aren't any? Why I was sure I would find some. But I didn't, and I know why.




The truth is that almost nobody drinks tap water from a boat's water system. For the last year I have been doing an informal survey about drinking water on boats. Very few admit to drinking water from their boat's system, but with only one exception they had elaborate water purification systems on board. The exception I think was younger at the time, and beat the odds. The second reason is most cases never get reported. You're queasy for a few days, and hopefully your body, or antibiotics makes it go away.

For almost everyone else, there was always a visceral and automatic reaction that was accompanied with a look of disgust, and a wrinkled nose. That implies to me that they weren't going to touch the water from a boat's tap, and I don't blame them. 

My theory is that we all instinctively know the tepid water that has been laying in the boats water system has been incubating unmentionable biologicals, and it should be kept away from our innards. In general we are right, and this is why bottled water abounds on boats

It's time to fill the water tank, and go for a cruise. You pull the hose out of the bilge that has been laying there for weeks. The warm water left in the hose has been growing molds and biofilms on its insides. You screw it into the hose bib on the dock that seagulls roost on, open the deck fill, stick the hose in, and turn it on. This takes a while, and the easy way to tell if the tank is full is to see if it's over flowing onto the deck. Oops it is, and you run to shut it off. Some of the water on the less than clean deck is now mixing with the ostensibly clean city supplied water and getting into your water supply.

Biofilms, and microbes from the hose and deck join their colleagues in the water tank. Growth rates in the warm water are staggering. Every 15 to 20 minutes one becomes two, to eight, and then sixteen. In a day, there are millions of creepy crawlers swimming in the tank along with their moldy friends.

The heating, and cooling of the day causes the water tank to breath in and out of its vent. The vent is regularly splashed with the seawater carrying with it microbes like E-coli which also migrates down the damp vent pipe. Vents whose screens have rotted away, if they had one in the first place allow insects to climb on in and rent some space.

Water that evaporates from the tank escapes out the vent leaving mineral solids behind that slowly accumulate on the sides and bottoms of the tank. Molds grow on damp tank sides, and in piping that has air gaps.

The coup de grace is delivered when your glass of tap water provides a new home for Giardia, and her friends like Legionella, Staphylococcus, E-coli, and don't forget the mold family.

There must really be a better way to design a basic boat water system. Better quality filtered vent systems, large openings in the tanks to allow for good cleaning, and inspection. Tank air vents could be installed so they could be easily accessed and inspected. Plumbing could be designed to allow aftermarket installation of filtration systems without jury rigging them into place.

I'm not going to lecture you on how to clean your water system, a lot of other people have written about this. My advice is that if you don't have a first class filtration system, just don't drink boat water from the tap, period. I have used unscented household bleach as a disinfectant because you can clearly smell it. That bleachy odor, means it's good to shower in, and wash your dishes with. If you don't smell it, don't use your water for anything.

Of course if you can really smell it, it's not going to be tasty water to drink. Adding too much bleach makes the water unsafe to drink. The general safe limit is two table spoons per ten gallons, and it needs an hour to thoroughly sterilize your water. By the way this is not guaranteed to kill everything in the water that could hurt you, but it's better than not doing anything. Some nasty things such as the commonly found Cryptosporidium  requires heavy doses of bleach to take them out of the picture and your intestinal track.

And if you don't use your water system at all, empty it, and periodically put a some bleach in the tank. There's no point in carrying around primordial soup in your boat. I'm pretty sure the theory is bunk. I have it on good authority that life on earth was seed by aliens.

All of the bugs pictured are real, and from top to bottom is Giardia, legionella, E-coli, and mold spores. It might be my imagination, but I'm not feeling all that well, and it's time to go, no I mean it, I really gotta go.

July 11 2012: A small postscript about the story.

I have read some of the forum comments about the story. I know it sounds scary, and I tried to make it that way, but you have no idea how many filthy water systems I have seen. In a south Florida summer, a closed boat under full canvas can easily reach 100+ degrees F. I have seen enough fetid water, moldy tanks, and fill hoses to last a life time.

There is a direct correlation between water temperature, and bacteria growth. For example Legionella thrives best at 35 C or 95 F. The point being warm water encourages bacteria growth rates. Some forms of black mold such as Stachybortys and Aspergillis are also dangerous. My other point was marine water systems are difficult to really clean. The next time you're in the bilge, look at the water tank, and see what you would have to do to give the inside a real cleaning, if you can access the interior at all.

If you regularly clean and sanitize your water system, and absent any filtration, it's safe enough to shower in and wash dishes with, but personally I still wouldn't drink it, and most don't. Bottled water is much safer, cheap, and tastes better. I had originally pitched the story line to a magazine along with a water testing for ten boats. A couple of live a boards, a few cruisers, a shiny new boat, and some others in between. The $400 dollar per boat testing costs sunk the concept on the spot. I still think it would be a good idea to empirically quantify the issue. No one has that I could find.

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