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#3
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![]() wrote in message ... On Sat, 15 Sep 2007 14:02:45 GMT, (Richard Casady) wrote: On Sat, 15 Sep 2007 16:11:47 +0700, wrote: A simple example: You decide you want to buy a barrel of crude oil, the price is in the newspaper every day, right? Now tell me what a barrel of oil is? Right off the top of my head I can think of several different sizes of barrels, 55 gal., 44gal., 200 Ltrs., etc. Bad example. The petroleum barrel has been 42 gallons since they used old herring barrels to haul crude in horse drawn wagons. It is a recognized item in the list of internationally accepted weights and measures. My calculator has it as 42 gal per bbl. By the way, a 55 gal drum holds that much so that you get 50 gal liquid capacity plus the necessary expansion space. So it's actually a round number. Casady No, good example as my company worked for just about every international oil company in Indonesia and every one of their contracts defines a "barrel" in the preamble to the contract. By the way is not 42 US gallons, it is 42 US gallons at 60 degrees F at sea level. :-) What's the temperature have to do with anything? I know what you're gonna say. You're gonna say volume decreases with temperature decrease and vice versa. But does that not also hold true for the measuring container? It's the same thought process those dummies who say to loosen the standing rigging for the winter storage period because the stays and shrouds shrink with the cold. But, I suppose they think the aluminum mast doesn't also shrink? Duh! Ya gotta think outta the box, man. Wilbur Hubbard |
#4
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On Sun, 16 Sep 2007 13:08:32 -0400, a troll wrote:
a "barrel"... is not 42 US gallons, it is 42 US gallons at 60 degrees F at sea level. :-) What's the temperature have to do with anything? I know what you're gonna say. You're gonna say volume decreases with temperature decrease and vice versa. But does that not also hold true for the measuring container? It's the same thought process those dummies who say to loosen the standing rigging for the winter storage period because the stays and shrouds shrink with the cold. But, I suppose they think the aluminum mast doesn't also shrink? Duh! Ya gotta think outta the box, man. Wilbur Hubbard Oh dear, I am going to regret this: the troll's not only wrong, but ugly about it too! Gas expands in volume 950 ppm per deg C So it's important to sell by mass (which is invariant) or by volume at a set temperature. It's not a lot in a tank of gas (so much for filling up in the cold pre-dawn) but it mounts up if you sell by the million barrels. Steel and aluminum expand at different rates: the linear rates are Steel 12 ppm /degC, Aluminum 24 ppm /degC So the time to ease the stays is when leaving a boat in warming weather, if at all. A sample 50 ft mast might need two or three turns easing on each rigging screw for 30 degrees C temp rise. But more care is needed with plastic rigging. That can really change with temperature. Brian Whatcott Altus OK |
#5
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On Sun, 16 Sep 2007 13:08:32 -0400, "Wilbur Hubbard"
wrote: wrote in message .. . On Sat, 15 Sep 2007 14:02:45 GMT, (Richard Casady) wrote: On Sat, 15 Sep 2007 16:11:47 +0700, wrote: A simple example: You decide you want to buy a barrel of crude oil, the price is in the newspaper every day, right? Now tell me what a barrel of oil is? Right off the top of my head I can think of several different sizes of barrels, 55 gal., 44gal., 200 Ltrs., etc. Bad example. The petroleum barrel has been 42 gallons since they used old herring barrels to haul crude in horse drawn wagons. It is a recognized item in the list of internationally accepted weights and measures. My calculator has it as 42 gal per bbl. By the way, a 55 gal drum holds that much so that you get 50 gal liquid capacity plus the necessary expansion space. So it's actually a round number. Casady No, good example as my company worked for just about every international oil company in Indonesia and every one of their contracts defines a "barrel" in the preamble to the contract. By the way is not 42 US gallons, it is 42 US gallons at 60 degrees F at sea level. :-) What's the temperature have to do with anything? I know what you're gonna say. You're gonna say volume decreases with temperature decrease and vice versa. But does that not also hold true for the measuring container? It's the same thought process those dummies who say to loosen the standing rigging for the winter storage period because the stays and shrouds shrink with the cold. But, I suppose they think the aluminum mast doesn't also shrink? Duh! Ya gotta think outta the box, man. Wilbur Hubbard Willie-boy I got admire you. you are the perfect example of the old adage that, "fools rush in where wise men fear to tread". A "barrel of oil" is a standard of volume measurement used in the Oil Industry. Just like gallon or liters, and since the volume of most liquids change with temperature or pressure the temperature of the liquid and pressure the liquid it is exposed to is specified. A standard contract definition will be something like "a barrel" shall be defined as 42 US gallons at 62 degrees F, at sea level. In reference to rigging changes at different temperatures they certainly do change in length with changes in temperatures. You can look up the coefficient of expansion of aluminum and stainless on the web or in most engineering handbooks. Of course, in winter the colder temperatures will cause the spars and rigging to contract and the aluminum mast will contract more then the stainless rigging so your comments on the necessity to loosen rigging for temperature change in winter is correct. Bruce in Bangkok (brucepaigeATgmailDOTcom) |
#6
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#7
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On Mon, 17 Sep 2007 23:06:17 GMT, Brian Whatcott
wrote: On Mon, 17 Sep 2007 19:16:16 +0700, wrote: .... In reference to rigging changes at different temperatures they certainly do change in length with changes in temperatures. ... in winter the colder temperatures will cause the spars and rigging to contract and the aluminum mast will contract more then the stainless rigging so your comments on the necessity to loosen rigging for temperature change in winter is correct. Bruce in Bangkok I'd hate anyone to take a Troll's sneer at face value like that. I'm thinking of a race boat with a carbon fiber composite mast. This material can have an extremely low thermal coefficient - as low as 1 ppm /degC. Most rigging would shrink more in Winter (but a few would expand when chilled, wouldn'tcha know?) Brian W Well, if you are designing a high tech racing boat why not use high tech synthetic rope for rigging. some of it is stronger then stainless cable and nearly zero stretch. Bruce in Bangkok (brucepaigeATgmailDOTcom) |
#8
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