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    Re: How Many Chronometers?
    From: Gary LaPook
    Date: 2009 Sep 20, 01:40 -0700

    I always look forward to George's input to our discussions. 
    
    
    George wrote:
    
    "I recall that as a child, British winters, in a house with only local 
    heating, were made tolerable at night only by using a hot-water-bottle (such 
    aids may be unknown and unnecessary in the USA). And I recall how rapidly 
    such a bottle would lose its heat, though wrapped in blankets with me, so 
    that before very long it was a pleasure to kick it out. I also recall the 
    use of a vacuum "Thermos" flask to keep cups of tea hot, and their failure 
    to do so for more than a very few hours. This in spite of the fact that some 
    pints of water were involved, a substance which has the highest 
    specific-heat of any, which means that it holds more heat, and keeps its 
    temperature, longer than anything else. Gary's crystal oscillator in a 
    blanket, without such heat-ballast, would not keep the outside temperature 
    at bay for long, but with a bottle of water to keep it company, he might 
    increase its thermal time-constant to a few hours; not for days, however."
    
    My comments:
    
    I agree that the watches, if kept in an insulated box, would eventually change 
    temperature to that of the ambient, the question is just how quickly. One can 
    make a small box out of insulating foam which is much better insulation than 
    the blanket that George shivered under after his hot water bottle lost its 
    heat on the cold winter nights of his youth. My suggested use of such a box 
    is to reduce the amplitudes of the daily temperature swings and other 
    relatively short term temperature changes. I like George's suggestion to add 
    a water bottle inside the box to add thermal inertia to the system. The 
    insulated box and the water bottle would constitute a "low pass filter" as to 
    temperature changes, only letting relatively low frequency, long term 
    temperature, changes affect the watches. 
    
    
    George wrote:
    
    "As for his "range of temperatures which are habitable for humans", there 
    might well be different views on that from different societies in different 
    eras. A week ago, I was looking over HMS Cavalier, a World war 2 destroyer 
    built in 1944; the sort of ship that escorted Arctic convoys to Murmansk and 
    Archangel in Northern Russia, Summer and Winter. ........
    
    .....The "bridge" got its name from an open lattice structure, that bridged the 
    gap between the top of the paddle-covers, to provide an all-round view. From 
    such a perch, steamers in their thousands were conducted across the North 
    Atlantic, the year round.. In thick weather, a lookout was expected to be 
    stationed at the fo'c'sle head; no shelter provided. These were considered 
    to be habitable conditions then, but I doubt whether Gary would describe 
    them so now."
    
    
    My comments:
    
    To my way of thinking, "habitable" is something different than "survivable." I 
    am certainly impressed by the courage and devotion to duty of the watch 
    standers on the Murmansk run and others who do their duty under harsh 
    conditions. Although I have never stood a watch north of the Kola Peninsula I 
    do have some experience working in fairly harsh weather conditions. I have 
    attached some photographs taken on a day when it was ten below zero 
    Fahrenheit when my artillery battery was firing our eight inch howitzers and 
    we worked in similar conditions on many occasions. Being an observer of the 
    human condition, I have observed many times that humans, when given the 
    opportunity, will seek shelter from temperature extremes. On the artillery 
    firing point the most popular man was the ambulance driver since he had the 
    only enclosed, heated, vehicle and my soldiers would all attempt to be his 
    best friend so they could sit in his ambulance and chat when not conducting 
    fire missions. Those who couldn't fit inside the ambulance would go into the 
    backs of other, unheated, vehicles to escape the wind until duty required 
    their presence out on the guns. I suspect that few, if any, of the brave 
    sailors that George talks about remained out on the bridge wing when their 
    watches were over but went back inside to more "habitable" conditions. 
    
    In addition to my many years in the army I also had the opportunity to observe 
    the human condition in the civilian world. I was a mailman in Chicago and I 
    had to be outside delivering mail every day of the year. This included the 
    days when record temperatures were set, 106º F (it's NOT a DRY HEAT) and -23º 
    F (-30.5º C.) (That's no longer the record, it's now -27ºF in Chicago.) I can 
    tell you that the sidewalks in Chicago are mighty lonely when it's that cold. 
    
    
    Humans have always attempted to modify the temperature of their living 
    quarters to make it "habitable", think CAVEMAN and FIRE. Based on this human 
    attribute, I think that most sailors, but not all, will find some way to 
    limit the range of the cabin temperature when the weather outside is nasty. 
    We read in the sailing press of hearty sailors visiting Antarctica but I 
    firmly believe that their boats have heaters. 
    
    Back to using cheap quartz watches for chronometers. I have stopped my 
    experiment since there is a very obvious change in their rates at -5º F 
    (-20ºC)compared to my room temperature which is very close to the 25ºC at 
    which quartz watches are designed to work. After accounting for the fact that 
    all three watches had been gaining every day, the three watches showed a 
    change of rate -4.6, -3.7 and -3.3 seconds per day when operated 45ºC colder 
    than the designed temperature. After running this result through the formula 
    for predicting this change in frequency it appears that the constant in that 
    formula, for these watches, should be .02 ppm rather than the commonly quoted 
    .04 ppm. Using this constant, a temperature change of +/- 5ºC from a cabin 
    temperature of 25ºC would only cause a change of rate of .04 seconds per day. 
    So if one is sailing a boat where the cabin temperature can be maintained in 
    this range then just keeping the watches below, possibly in an insulated box 
    with a water bottle, then using these watches is a good option. 
    
    When I come back from the beach here in southern California with some beer and 
    ice left in my cooler, I place the cooler out on my patio. I have noticed 
    that there will still be ice left in the cooler four days later. This tells 
    me that a cooler provides great insulation and that the ice maintains the 
    temperature at the freezing point very effectively. So, if the cabin can't be 
    maintained at around 25ºC then an alternate way to stabilize the watches can 
    be utilized. Simply buy a small cooler and put the watches and some ice in it 
    and establish their rates at this cooler temperature, they should be running 
    slow. Since the ice will maintain the temperature at zero very accurately the 
    rates of the watches should also be very stable but this only works if the 
    cabin temperature is above freezing. If the temperature is below freezing in 
    the cabin simply melt some ice on the stove and put the water, after it has 
    cooled back to the freezing point, in the cooler and the water, as it slowly 
    freezes, will also maintain the temperature exactly at zero. If you can't 
    melt water because you do not have a stove then you can resort to the duct 
    tape and belly method which should work everywhere. This works best for those 
    who have consumed a lot of beer during their lifetimes to provide a 
    horizontal, table like, upper surface on which to tape the watches.
    
    gl
    
    
    
    
    
    
    George Huxtable wrote:
    > In [9766], Gary recorded a disagreement with my suggestion that one can do 
    > little to protect a sensitive object, such as a crystal oscillator, from 
    > environmental changes in ambient temperature, by such means as wrapping it 
    > in blankets. I claimed that this could have only a short-term effect, and 
    > that the ambient changes would always get through in the end.
    >
    > He wrote-
    >
    > "So I disagree with George to the extent that if the watches are kept in
    > an insulated box, to limit the effect of diurnal changes in cabin
    > temperatures, then the change in rate will only happen based on long
    > term changes in ambient temperature, say on a cruise from the Caribbean
    > to England. But, if the cabin is kept in a range of temperatures which
    > are habitable for humans then the change of rates can be kept to a small
    > number."
    >
    > I recall that as a child, British winters, in a house with only local 
    > heating, were made tolerable at night only by using a hot-water-bottle (such 
    > aids may be unknown and unnecessary in the USA). And I recall how rapidly 
    > such a bottle would lose its heat, though wrapped in blankets with me, so 
    > that before very long it was a pleasure to kick it out. I also recall the 
    > use of a vacuum "Thermos" flask to keep cups of tea hot, and their failure 
    > to do so for more than a very few hours. This in spite of the fact that some 
    > pints of water were involved, a substance which has the highest 
    > specific-heat of any, which means that it holds more heat, and keeps its 
    > temperature, longer than anything else. Gary's crystal oscillator in a 
    > blanket, without such heat-ballast, would not keep the outside temperature 
    > at bay for long, but with a bottle of water to keep it company, he might 
    > increase its thermal time-constant to a few hours; not for days, however.
    >
    > As for his "range of temperatures which are habitable for humans", there 
    > might well be different views on that from different societies in different 
    > eras. A week ago, I was looking over HMS Cavalier, a World war 2 destroyer 
    > built in 1944; the sort of ship that escorted Arctic convoys to Murmansk and 
    > Archangel in Northern Russia, Summer and Winter. She was refitted in 1957 
    > and retired in 1974. Yet still, she had a completely open bridge, without 
    > windows, and only a dodger to keep the weather off. And I was rather 
    > surprised to find, tucked away on that open bridge, sheltered from rain but 
    > from nothing else, electronic gear such as a radar display.
    >
    > How, I wonder, would modern American bridge-teams, sheltered from the world 
    > in their air-conditioned cocoons, without even an open bridge-wing to walk 
    > out on to, have fared under such conditions? Or in the environment accepted 
    > by some present-day small-craft sailors, the ones that venture away from 
    > tropical trade-wind sailing?
    >
    > The "bridge" got its name from an open lattice structure, that bridged the 
    > gap between the top of the paddle-covers, to provide an all-round view. From 
    > such a perch, steamers in their thousands were conducted across the North 
    > Atlantic, the year round.. In thick weather, a lookout was expected to be 
    > stationed at the fo'c'sle head; no shelter provided. These were considered 
    > to be habitable conditions then, but I doubt whether Gary would describe 
    > them so now.
    >
    > Polar explorers, by the way, would carry sledge chronometers: pocket 
    > watches, slung round their necks inside their furs, essential for guiding 
    > them back to base along the correct longitude. When Shackleton's Endurance 
    > went down in the Antartic ice in 1915, the ship's box-chronometers were 
    > abandoned with the ship, and from then on the expedition relied on four such 
    > pocket-chronometers. Only one of those remained in working order throughout 
    > that remarkable journey from Elephant Island to South Georgia, being 
    > essential for Worsley's feat of small-craft navigation.
    >
    > Together with Brad, I'm intrigued by the type of yoga that Gary adopts to 
    > enable him to read a chronometer that's duct-taped to his belly.
    >
    > George.
    >
    > contact George Huxtable, at  george@hux.me.uk
    > or at +44 1865 820222 (from UK, 01865 820222)
    > or at 1 Sandy Lane, Southmoor, Abingdon, Oxon OX13 5HX, UK. 
    >
    >
    > >
    >
    >   
    
    
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