Monday, 21 October 2019

Riding the Munga? Be sure to pack your Bottle-Sox.

During Munga 2018 I found myself in the the heart of the Tankwa Karoo in the middle of the day. The temperature was in the mid 40's - in the shade. A scorching wind added to my discomfort. I was dehydrated and although I had water it was as hot if not hotter than the scalding heat I found myself in. Hotter because my bottles were exposed to the midday sun. I knew I had to drink but water the temperature of hot tea wasn't going to fix my immediate problem. 

 

There are some people who suggest that you should drink warm water rather than cold water to aid your digestion. Did I mention that I was in the middle of the Tankwa Karoo and not dinning at a Ritz-Carlton hotel? In any case those people are delusional and very wrong. 


From the research I have read it seems that If you are hot and dehydrated the temperature of fluids you drink should ideally be 26°C (considered to be room temperature) or lower—certainly lower than body temperature. As you get dehydrated your body starts reining in  the amount you sweat to preserve your state of hydration. Ingesting fluids above room temperature can trigger an episode of extreme sweating. Think about how a cup of tea or coffee after a hot day ride triggers rivulets of sweat that cascade over your face or down your back. 


It's a delicate balancing act of trying to retain hydration and still have a measure of thermal regulation. It's a space people should avoid at all costs. Unfortunately given the extreme environmental conditions of an ultra-endurance race that traverses a desert in the height of summer it's a reality that most Munga athletes will be faced with.


It's a complex subject that is further complicated when the fluid isn't just plain water and also contains carbs. In short, hot and sweet is a useless combination to be swilling out of your water bottle or sucking through the tube of your hydration pack. I'd had this problem before and knew I had to get the temperature of the water down if I wanted it to do me any good. 


To cool my water I wrapped one of my bottles in a buff and dampened it with a little water from another bottle. By the time the buff had dried 20 minutes later the water was cool enough to drink. It was a case of necessity being the mother of invention. 


Evaporative cooling is not a new idea and I have even designed and built my own coolers but before my desperation driven solution in the Tankwa it never occurred to me that the principles could be put to good use to cool water while riding through hot arid regions. 


To understand how effective this cooling can be lets examine the science behind why this works. Refrigeration 101 teaches that things are not made cold but rather that heat is removed. It appears a subtle difference but it's an important one. During the phase transition of water to water vapour (changing from a liquid to a gas) a lot of heat is used to achieve that change and that heat is dissipated in the resultant gas. We experience this principle in action when we get hot. The heat causes us to sweat and the sweat evaporates and our skin is cooled. 


I'm old enough to remember the canvas bags that people dangled from the bumpers of their cars and bakkies in the 70s in order to have cool drinking water. Being made from canvas meant the bags weren't waterproof and as a result they continuously "leaked". The outside was always a little damp and it was that continuous evaporation of the outside skin that resulted in the heat being removed from the water within. 


If you place a standard bottle of water in the shade the temperature of the water will eventually be the same as the ambient temperature. Stand it in the sun and it will likely get hotter than ambient temperature. It doesn't matter if there is wind flow. The plastic makes it impervious so there is no water evaporating and the chill factor is zero. The temperature will be the same as that measured with a thermometer. That is, with a dry bulb thermometer. A wet bulb thermometer shows the temperature that includes the evaporative effect of wet and wind. Essentially it's the temperature as measured by a thermometer that is placed in a wet cloth that has airflow over it. This is an important part of how cold you can get the water in your bottle. Stick with me. 


There is a direct link between air humidity (relative humidity) and wet bulb readings. In high humidity conditions the evaporation rate is greatly reduced as compared to arid conditions. Practically you have probably experienced how long it takes to dry a towel in midsummer humidity such as we get in Durban compared to the swift drying time of a wet towel in the dry Highveld air of a Johannesburg winter. 


The less humid (drier) the air the greater the differential between dry and wet bulb readings. Evaporative coolers (often called swamp coolers) used to cool buildings make use of this difference. An evaporative cooler used in Johannesburg is a lot more effective than one used in Durban. As a consequence you don't see as many evaporative coolers being used in humid coastal conditions. 


I couldn't find any reliable dry/wet bulb readings for South Africa but found some for the USA. I figure that Las Vegas in Nevada is similar to the arid conditions we have in the Karoo. When it's 42°C in Vegas the wet bulb temperatures are often as low as 19°C.  That's a huge differential. Good evaporative coolers reach efficiencies of up to 85%. That is, they lower the air temperature to 85% of the difference between dry and wet bulb temperatures. In the Vegas example above they should be able to lower the air temperature going into the building from 42°C to 23°C. 


Armed with that information I worked on finding a permanent solution. I considered making a fabric sleeve that could slip over a bottle. It had to be a material that would easily absorb and hold water and then easily release that water via evaporation. When you are riding in a desert water is precious, I don't want to waste water trying to wet the sleeve. 


I considered different materials including neoprene before the obvious solution popped up —orphan socks. Who doesn't have a collection of those? I found a lonely ankle high sock and slipped it over a bottle. I used a white sock but after a few hours on the trail it may as well have been a light brown one as it is now a permanent shade of dirt. 




The option of neoprene or a thicker sock was discarded as the bottle wouldn't fit easily in my normal bottle cage and neoprene proved more difficult to wet. I never got around to testing it's evaporative qualities. 


It turns out my ankle sock worked fine. I like that it's a little too long as I fold it over at the top. This forms a cuff that acts as a little water reservoir that then wicks down into the lower part as it dries through evaporation extending the cooling effect. 


Here is a summary of my tests. 


I used two bottles which were placed in the sun and left to stabilise. I recorded the temperatures. I then placed a sock over one and wet the sock. I measured both after 30 mins after which I wet the sock again and measured the temperature after another 20 minutes. 

To simulate the effect of cycling I had a fan blow air over the bottles as they stood in the sun. 


Ambient temperature (shade) 30.5°C

Bottles in sun stabilised 31.5°C


30 mins later

Ambient 30.6°C

Control 31.2°C

Wet Sleeved bottle 21.2°C


Additional 20 mins

Ambient 30.5°C

Control 31.2°C

Wet Sleeved bottle 18.1°





Observations 


The cooling effect of the wet sock seems to surpass the efficiency of a building evaporative cooler. This based on the fact that I have an evaporative cooler installed in my home and the temperatures do not get as low as those I measured in the wet sleeved bottle. 


I would expect to reach efficiencies approaching 100%—that is, the same as wet bulb temperatures. This seems obvious as we are effectively employing the wet bulb methodology—wet fabric and air flow. Having said that, in the arid conditions of the Karoo the sock would dry quicker and it might be too quick to effectively reduce the temperature through the entire volume of water in the bottle. If you were able to wet the sock twice you would get close to wet bulb temps as demonstrated by the results I got from wetting the sock a second time. The fact that the sock would dry quicker in the Karoo isn't a bad thing as the faster it evaporates the  greater the cooling effect. 


In practice you would probably wet the sock at a water point which would keep the bottle contents cool for about an hour. After that, given the scarcity of water I would only wet the sock about 20 mins before I planned to drink from it. It would be a waste of good water to continually wet it. Best thing is you can wet the sock with any water even if it's dodgy. You can dip it in reservoirs that you pass and If you're desperate you can even pee on it.


I have tested this method while out riding and was able to wet the sock 5 times using about 250ml of water. It's a fair price to pay for cool water. 


Once the bottle is empty you can either top it up or move the sock to another bottle. 


The effectiveness of this method on an insulated bottle would be reduced. The close contact of wet sock/bottle plastic/water of a standard bottle makes the heat transfer efficient. An insulated bottle designed to keep water cooler for longer would have the same inhibiting insulation effect when trying to pull heat out of the bottle contents. 


Traversing the Karoo in summer has given me fresh appreciation for plain cool water. I'm definitely taking some socks along for the ride and I suggest you raid your sock draw and give it a try ahead of the Munga. If you do try it come November 27th I'm sure I won't be the only one sporting ... hmm we need a catchy name... let's go with Bottle-Sox. Cheers!


Friday, 15 March 2019

Stoffel

Having traversed the Karoo many times on both the Freedom Trail and The Munga I have seen countless wind driven water pumps - windmills. When it's hot and you are thirsty they become more than an interesting feature. I have often stopped at windmills to fill my bottles and quench my thirst and at times I've taken a cooling dip in the adjacent reservoirs.

Apart from riding my bike I dabble a bit in creative writing. When faced with the task of writing a short story on water my thoughts went immediately to the Karoo and these amazing machines. The following story has nothing to do with cycling but has its genesis in my experiences riding my bike through the harsh yet beautiful landscape that is the Karoo.

Stoffel

The rotor of the old wind pump turned slowly in the morning breeze, aged metal creaking and clunking with every revolution. It hadn't pumped water for the last few years but in spite of that, as if aggrieved by its retirement, it continued to rise to the challenge every time the wind ran its fingers through its rusted vanes. It stood as a sentinel over the electric pump nestled between its uprights.

My father had installed the new solar pump a year ago when the land was put back into rotation and the old wind pump was deemed uneconomical to repair. The subzero temperatures of the winter nights had caused the water to freeze and burst the outlet pipe.

It was still bitterly cold so I sat on the tail gate of the Hilux, thermos flask of coffee in hand, and waited for the sun to gift its warmth to the frosty morning. It was good to be back home after a two year hiatus. My professional life had kept me in the city for far too long this time. Sitting there looking out over the land of my youth I vowed to make the trip home more often. It occurred to me that I had this thought every time I returned. Never mind, I was here now and it was good. My soul breathed deeply of the arid morning air.

The various wind pumps, scattered across the sheep camps of our Karoo farm had been allocated names according to the lands they watered. Many stretching back so far I had no idea as to their origins. Names like New Land, Old Soldier, Vleiland, Oorlog and Bobbejaanskloof.

This pump was unique in that until recently it was simply known as the far pump but had since been renamed as Stoffel's Windmill. Of all the pumps that Stoffel repaired, he declared that this particular one was his favourite. It was the most decrepit pump on the farm and had probably outlived its useful life span by a few decades. Under Stoffel's care it had survived a number of close calls, finally succumbing to technological creep.

Stoffel could best be described as an itinerant wind pump repair man. Over the years Stoffel would arrive by bicycle when summoned to fix a wind pump that was damaged beyond the scope of my father's ability. He had no tools and merely brought decades of experience underpinned with a passion for these old ladies of the plains as he called them.

In the days before cell phones a call was placed, a message left and Stoffel would duly arrive on his dikwiel bicycle, his lunch box tied to the carrier of his bike. In spite of its obvious age, with worn tyres that showed the huge distances travelled, the bike was always clean and ran as smooth as any machine I had ever seen. A faithful dog trotted behind. I remember two over the years, both known simply as "Hondjie". It is an image etched into my earliest memories.

Stoffel would be instantly surrounded by our barking dogs. He fussed with every one until they settled. The cacophony would serve to alert my Pa that Stoffel had arrived. A short ritual would follow.
"Hierdie keer, gaan sy nie werk nie. She's not going to work this time," said my Pa.
Stoffel would nod in agreement and reply to the effect that the pump was probably buggered for sure.

He would then take a few minutes to sit up against the wall of our metal shed, eyes closed, the morning sun falling on his weathered face and smoke a home rolled cigarette while my father started loading the metal trunk and other boxes that contained all the tools and pump parts onto the back of the bakkie.

Cigarette extinguished, Stoffel would take off his right veldskoen and carefully remove and pocket the elastic band that he used to keep the leg of his long pants away from the bicycle chain. Shoe refitted and laces tied he would rise, place his wide brimmed leather hat on his balding head and smooth his khakis before making his way over to the bakkie where he would assist my father in loading the chain block hoist.

Toolbox, hoist and dog loaded they would head off together to the far reaches of the farm to fix the errant pump.

There were countless times that I stood by the kitchen window watching that bakkie bounce down the rutted farm road, my father and Stoffel sitting side by side in the cab with Hondjie perched nonchalantly on the back.

In my fourteenth year, back on the farm during the school holidays, my father announced that Stoffel would be around in the morning to fix the pump at the far end of the kloof. He said I could drive well enough now to use the bakkie and take Stoffel up there.

I watched the hands of my bedside clock slowly chase each other all through that long night. Sunrise found me sitting at the breakfast table, bakkie keys in hand. I had long since given up pushing food around my plate. I was too excited to eat. The contents of the now empty coffee pot, a permanent feature on the anthracite stove in our kitchen, added to my jitters. My ears pricked at every sound from the yard as I waited for Stoffel to arrive. Eventually the baying of the hounds heralded his arrival.

Jumping up I hurried toward the yard. I stopped just short of the last corner, gathered myself and then strolled up to greet Stoffel. I announced that I would be doing the driving and helping that day and that the pump was probably a write-off. Stoffel to my surprise didn't reply. He merely nodded, removed a cracked leather tobacco pouch from his lunch box and settled against the shed. Nonplussed I wandered back into the house and observed Stoffel from the kitchen window.

As he stubbed out his cigarette I sauntered outside and waited for him beside the bakkie.
He walked over, gave the rear of the bakkie a cursory glance and fixed me with his deep set eyes. "Laaitie, waar is die trommel?"
The question stung, a flush rose in my face. Firstly, he referred to me as a boy, which I was, but it didn't sit comfortably with me. Secondly, I had forgotten to load the tool box onto the bakkie - I had stumbled at the first hurdle.

After a moments delay Stoffel walked up, patted me on the back, and announced that he would come give me a hand to load the box and hoist on to the bakkie. In that moment we set in motion a ritual that was rolled out every time Stoffel and I worked together. Whenever he arrived at the farm and I was there, he would ask, "Laaitie, waar is die trommel?", a small smile stirring at the corners of his mouth. It no longer stung. In fact it filled me with joy and pride. It was Stoffel's way of acknowledging me. It was intensely personal. It felt good.

That first day when we arrived at the broken pump I watched him in action. He moved over to the pump, put the brake on and climbed the tower and gave the vanes and tower a careful inspection. After scrutinising the wind pump for a full minute he started talking to it. He sympathised with her condition and carefully explained what was required to allow her to once again fulfil her role in drawing life sustaining water from beneath the dusty surface.

He breathed a life and personality into the collection of metal parts. I witnessed this ceremony many times, just as I witnessed him caress them back to full health.

Oftentimes it was back breaking work and we worked side by side but he would never lose his patience or believe any pump was beyond repair. He would tell me that all they needed was a little understanding and a gentle hand. I saw that gentle hand bring many a pump back from the brink.

Stoffel explained that we would need to replace the leather cup and repair one or two vanes. I had no idea of the work required and gave him a cheerful thumbs up. Many hours later having pulled the pipes and rods to replace the leather cup we lowered the repaired components back down the hole.

With the pump repaired we retired to sit on the wall of the small reservoir to wait for the wind to put our handiwork to the test.

I was exhausted and hungry. I opened the basket containing the padkos my Ma had packed.
"Laaitie," said Stoffel, "Ja, that's not too clever. Maybe you should go get some lappies out the bakkie first."
I looked down at the basket, greasy hand prints showed where I had touched it. I was covered in grease from the tips of my fingers to the bottom of my boots. Stoffel by contrast with finesse born of experience had managed to restrict the mess to just his hands. I went to the bakkie and returned with two cloths. I handed one to Stoffel and set about cleaning myself with the other. Hands cleaned we examined the contents of the basket. Dividing the food equally we spent the next while alternating between chewing and chatting about nothing in particular.

Once finished, Stoffel carefully unrolled his tobacco pouch and began meticulously arranging shag tobacco on a square of paper.
"Tell me Laaitie," he began. "What is Cape Town like?"
He knew I went to boarding school in Cape Town and he listened with interest as I regaled him with tales of the Mother City. In the years that followed he would often ask me to tell him more about that mystical place that captivated his imagination. I told him of the mountain draped in an ethereal blanket of cloud. Of waves driven across the oceans rising up majestically before crashing down defeated on golden sands. Of days when the wind was so strong that one daren't venture outdoors. Of vineyards that swathed the mountain slopes is green and golden splendour. I stopped short of telling him about the traffic congestion, ramshackle shanty towns, of poverty and the homeless that roamed the streets - these images had no place in the heart of the man who believed this fairest of Capes smiled equally on all who dwelt there. He said nothing as I told him these stories. He would simply listen and slowly go about the business of fashioning his cigarette. His curiosity sated he would simply nod and say "It is so."

He would then remove himself to light his cigarette and enjoy a meditative moment, always careful to place himself so his smoke didn't drift in my direction.

We spent countless hours waiting for the wind to rise and energise the vanes. We could have cranked the pump by hand, and had done so on the odd occasion, but Stoffel believed the pump should be spared that ignominy and be afforded the opportunity to show its worth in its own time. Looking back I can see that he took the same approach with me. I unconsciously absorbed so much from the man. Nothing was forced, he simply drew me in, piqued my interest and nurtured me. He never told me to do anything but I always knew what he expected.

On one occasion while waiting for the wind, he secured the head of the pump and opened the cover of the gear box. He commented that it was a good thing that Oom Stoffel had come to visit on this particular day. "Never mind, a little oil and we can have you sorted out."
On cue I grabbed the can of oil and scrambled up the tower to see what it was that needed fixing. Stoffel then took the next few minutes explaining the workings of the gearbox and the maintenance required to keep it in good condition.

Sometimes while waiting for the wind, Stoffel would busy himself with oiling rusted gate hinges or repairing fences. He would patiently show me how to fasten the wire strands with short pieces of draad to ensure the fence would be properly tensioned for years of trouble free service. On occasion he would point out the various plants or small animals we came across taking pains to explain how they meshed into the life cycle of the Karoo. At other times he would simply recount folklore stopping occasionally as if assessing whether there was any truth in the tale before continuing with added vigour.

His voice bore evidence of decades of considerable tobacco and alcohol consumption, the gravelly base overlaid with shrill overtones as he added emphasis. And yet, when working on the pumps his voice, barely audible, would come out as a soft hiss as he kept up a constant monologue with the machine.

If time allowed he would remove twisted vanes and spend an hour or two gently forging them back into shape. The pinging of metal on metal as he hammered against a small piece of railway track that he used as an anvil would create a steady rhythm over which his voice would rise in wordless song, the tone so sweet it belied the rough quality of his speaking voice. At those times I would simply sit in the shade of a thorn bush and allow the soothing melody to wash over me.

When the wind eventually set the blades in motion Stoffel would shuffle back to the pump. I learned there was no sight that pleased him more than that of water pulsing into a reservoir. He would cup his hands and drink deeply of the cold water that had spent countless years percolating through the ancient rock below. He would declare his satisfaction every time with the words, "It's not brandy but it's still very good".

He constantly reminded me that water was the most valuable resource on the planet. One day he mused at the possibility of the greatness that might have sprung from the very pump we had just fixed. He spoke of the unbroken journey of the water, through the sheep, all the way through to a world class athlete somewhere in the world. He told the story with so much detail and enthusiasm, his voice rising and falling as he did so, that I imagined that athlete, face heavenward, arms thrown back with chest thrust forward as they triumphantly broke through the finish line tape.

At the end of each repair job I would drive Stoffel back to our homestead. After helping me stow the toolbox and hoist, he would strap his lunch box to the bike and then mount up for the homeward journey.

If we worked late into the evening and I offered him a lift, he refused. He claimed to enjoy the exercise but I suspect he was a proud man and he would rather make his way to and from work under his own steam. As he pedalled off he would remind me to tell my Pa that it was good.

I would go inside and at a raised eyebrow from my Pa, I would merely repeat what Stoffel had said. My father just nodded and never asked what had been done. It was simple, if Stoffel was satisfied, then so was he. There was never any talk of payment or a reconciling of work done. In later years when I asked about it I was told that they had an arrangement. I never figured out what that arrangement was but it appeared they were both comfortable with it.

My attention was drawn back to the present. The wind had abated, the mechanism stilled and a mantle of silence blanketed the morning. The wind pump, towering above me, stood mute and yet proud. A golden wash drenched the structure as dawn peeped over the top of the kloof. I saw a discarded piece of fence wire lying on the ground near the bakkie. I smiled; Stoffel would have muttered his disappointment before picking it up. He had a thing about tidying up. I suspect he lived his life that way.
"Leave the place the way you would like to find it," he would say. "It doesn't matter if it isn't our mess. We were the last ones to be here so we need to sort it out."

And so it was, after every job we would return to the yard with a mass of tangled wire and other assorted bits of junk tossed in the back of the bakkie. The places touched by Stoffel were clear of clutter. He left only function and order in his wake.

I soon came to realise that many, if not all the repairs entrusted to Stoffel were well within the scope of my father's ability and after a short while within mine. It was my father's way of supporting Stoffel and I think he engineered it so that my life and values were influenced by the man. Stoffel possessed no wealth that I was aware of but was rich in spirit. He valued people above money, the land above possessions and the simple life rather than the trappings of kings.

It is easy for a farmer to love his land. Stoffel, as far as I knew, owned no land and probably lived in a tiny two room house typical of the settlement just up the road from our farm. He taught me to love the land, all of the land as well as its people without exception.

There came a day when the phone call went unanswered. That chapter of my life ended without fanfare. To my shame I did not know where Stoffel had lived or anything significant about his life or family. He gave to me in abundance and yet I hadn't bothered with taking the time to find out more about his life. He was private like that. He never spoke of himself but always had time to extol the virtues of those around him.

With the damaged pipe defrosted I could start the repair. My father had used a cheap PVC pipe where a more substantial pipe was the option of choice. He had settled for convenience over function. Stoffel would have frowned on his effort—convenience had no currency in his world. I opened the trommel, removed a knife and used it to slice off the damaged section of pipe.

As I looked to fold the blade away I stopped. There was nothing remarkable about the blade. Its dull surface and blunt edge, while adequate for the job, was unimpressive at best. It was functional. I turned it over in my hand appreciating the gaudiness of it. In spite of its appearance it was precious. It was a gift from Stoffel. I remember the moment he gave it to me a few days after I turned fifteen. He arrived at the farm and without explanation handed it to me. It was gift wrapped in a plastic Checkers shopping bag. I unravelled the package and the ugliest penknife I have ever seen tumbled out into the palm of my hand. I looked up at Stoffel.
"Ja, it's an ugly bitch," he said, "But it works and every boy should have a knife."
He went on to explain that he had received it as a birthday present. He already had one so he kept this one for me.

Turning that conversation over in my mind later that night I was struck by the fact that he actually celebrated birthdays. Obviously he had but I had never considered it before. In my mind he was as timeless as the Karoo itself with neither a beginning nor an end. He, it seemed, just like me and mine also marched to the drum beat of time.
Smiling I folded the knife and slipped it into my pocket and silently thanked Stoffel for the gift. Now that he was gone I missed him. He was my colleague and mentor. Beyond that he was my friend.

Finishing up I packed the tools away. I reached down and picked up the discarded wire and tossed it into the back of the bakkie. It rattled against the trommel. Then I waited. Not for the wind this time, but for the sun to play its fingers over the panel. With the rays converted into electricity the pump would spin up and fill the reservoir.

A short while later I heard the distinct sound of water dripping into the reservoir. I grinned. The frost layer on the rusted outlet pipe of the aged pump had begun to melt, dripping into the water below with a bell-like plink. It seemed the old wind pump would not be silenced, any more than the example and lessons of Stoffel that still found traction from beyond the grave.