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Nav wrote: Flying Tadpole wrote: katysails wrote: MC snorted: Nah, I believe his boat is on a fresh water lake. Good one! LOL Another one who doesn't know what they're talking about when it comes to the Great Lakes.... I'd fire up antoher verse of Edmund Fitzgerald, but it's far too good and far too serious for this forum... You missed the pun too? You must be tired! Your salty pun was just too deep for me. Now that I've gone back and looked at it again, I wish I hadn't... -- Flying Tadpole ------------------------- Break Away, Sail Away and putz away now at http://music.download.com/internetopera |
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Nav wrote: Flying Tadpole wrote: Scott Vernon wrote: "Martin Baxter" wrote ahh that'll do but to put it as simply as possible, fresh water is lighter and thinner than salt so it gets in easier. Thinner? You have some viscosity data to back this up? More likely fresh water exhibits a higher osmotic pressure because the difference in water concentration is greater in fresh than brine. (osmotic pressure being proportional to the differences in concentration on either side of the membrane) Even though Marty has the clap, he still sounds smart. Or perhaps a faint fairy clap? My memory which may be atfault lo, these many years, is that "osmosis" and "osmotic pressure" are labels describing a process which is known to happen and easily demonstrated and measured, just like gravity and which, just like gravity, no-one knows what it actually is. Nav (or others) here's your chance to put the Tadpole down. It's been a long time since I consciously studied physiology. Why would telling you someting about science be putting you down? By the way, osmotic pressure is derivable from first principles (see thermodynamics). Oops. Yes it is. My tired brain must have been confusing faint echoes of membrane transport systems... -- Flying Tadpole ------------------------- Break Away, Sail Away and putz away now at http://music.download.com/internetopera |
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Nav wrote: Martin Baxter wrote: OzOne wrote: On 29 Jun 2004 12:11:28 GMT, (Bobsprit) scribbled thusly: Can you explain why the percentage of boats that have blisters in fresh water is higher than in salt? I know that osmosis occurs faster in fresh water...something to do with density/salinity factor I think. Can you explain in a clear manner? Thanks, RB ahh that'll do but to put it as simply as possible, fresh water is lighter and thinner than salt so it gets in easier. Thinner? You have some viscosity data to back this up? More likely fresh water exhibits a higher osmotic pressure because the difference in water concentration is greater in fresh than brine. (osmotic pressure being proportional to the differences in concentration on either side of the membrane) Very close, but the osmotic pressure of fresh water is low. I expected a blsitering reply from you... -- Flying Tadpole ------------------------- Break Away, Sail Away and putz away now at http://music.download.com/internetopera |
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OzOne wrote: On Wed, 30 Jun 2004 10:30:22 +1200, Nav scribbled thusly: That's warm but is it warmer than the fresh water you are thinking about? Cheers Assume the same temp.....must be a shallow lake. Hey Taddy, what's the temp in your pond in summer? Around 20deg C. Never gets really warm (it's shallow and maritime, with strong winds). Note that the vineyards (Langhorne Creek) around it are actually classified as "cool climate"!!! because of the sea breezes. Winter temperatures, try about 8degC On blisters, I wouldn't have thought warmer would have made much impact compared with teh greater osmotic differential between fresh water & the pockets in the glas, and salt water and the pockets in the glass, but I'm ever ready to learn, as always. -- Flying Tadpole ------------------------- Break Away, Sail Away and putz away now at http://music.download.com/internetopera |
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Taddy stated: I'd fire up another verse of Edmund Fitzgerald, but it's far
too good and far too serious for this forum... Speaking of which, Gordy L. almost died this past year...that would have been a very bad thing for folk music...and for the sailing world.... -- katysails s/v Chanteuse Kirie Elite 32 http://katysails.tripod.com "Women and cats will do as they please, and men and dogs should relax and get used to the idea." - Robert A. Heinlein --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.690 / Virus Database: 451 - Release Date: 5/22/2004 |
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katysails wrote: Taddy stated: I'd fire up another verse of Edmund Fitzgerald, but it's far too good and far too serious for this forum... Speaking of which, Gordy L. almost died this past year...that would have been a very bad thing for folk music...and for the sailing world.... To be honest, I was startled to find he was still alive at the last winter olympics in Canada... -- Flying Tadpole ------------------------- Break Away, Sail Away and putz away now at http://music.download.com/internetopera |
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OK so is there a big difference in viscosity?
Cheers OzOne wrote: On Wed, 30 Jun 2004 10:30:22 +1200, Nav scribbled thusly: That's warm but is it warmer than the fresh water you are thinking about? Cheers Assume the same temp.....must be a shallow lake. Hey Taddy, what's the temp in your pond in summer? Oz1...of the 3 twins. I welcome you to crackerbox palace,We've been expecting you. |
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Flying Tadpole wrote: Nav wrote: Flying Tadpole wrote: katysails wrote: MC snorted: Nah, I believe his boat is on a fresh water lake. Good one! LOL Another one who doesn't know what they're talking about when it comes to the Great Lakes.... I'd fire up antoher verse of Edmund Fitzgerald, but it's far too good and far too serious for this forum... You missed the pun too? You must be tired! Your salty pun was just too deep for me. Now that I've gone back and looked at it again, I wish I hadn't... Even a poor pun is better than no fun! Cheers |
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OzOne wrote: On Wed, 30 Jun 2004 12:50:54 +1200, Nav scribbled thusly: OK so is there a big difference in viscosity? Cheers Nah. bugger all...but there is a diference. So you'll accept it's all in the osmotic pressure? Cheers |
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OzOne wrote: On Wed, 30 Jun 2004 08:40:38 +0930, Flying Tadpole scribbled thusly: OzOne wrote: On Wed, 30 Jun 2004 10:30:22 +1200, Nav scribbled thusly: That's warm but is it warmer than the fresh water you are thinking about? Cheers Assume the same temp.....must be a shallow lake. Hey Taddy, what's the temp in your pond in summer? Around 20deg C. Never gets really warm (it's shallow and maritime, with strong winds). Note that the vineyards (Langhorne Creek) around it are actually classified as "cool climate"!!! because of the sea breezes. Winter temperatures, try about 8degC Brrrrrr! On blisters, I wouldn't have thought warmer would have made much impact compared with teh greater osmotic differential between fresh water & the pockets in the glas, and salt water and the pockets in the glass, but I'm ever ready to learn, as always. Yep, me too. You might also wonder why blisters around the water line are more common. Ask Doug -he's seen plenty! Speaking of whom, I wonder if his fix up is still OK. Cheers |
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Nav wrote: Flying Tadpole wrote: Nav wrote: Flying Tadpole wrote: katysails wrote: MC snorted: Nah, I believe his boat is on a fresh water lake. Good one! LOL Another one who doesn't know what they're talking about when it comes to the Great Lakes.... I'd fire up antoher verse of Edmund Fitzgerald, but it's far too good and far too serious for this forum... You missed the pun too? You must be tired! Your salty pun was just too deep for me. Now that I've gone back and looked at it again, I wish I hadn't... Even a poor pun is better than no fun! Fun? FUN?? What do you think you're doing??? Have you learnt _nothing_ from your time on this newsgroup???? -- Flying Tadpole ------------------------- Break Away, Sail Away and putz away now at http://music.download.com/internetopera |
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OzOne wrote: On Wed, 30 Jun 2004 13:04:09 +1200, Nav scribbled thusly: OzOne wrote: On Wed, 30 Jun 2004 12:50:54 +1200, Nav scribbled thusly: OK so is there a big difference in viscosity? Cheers Nah. bugger all...but there is a diference. So you'll accept it's all in the osmotic pressure? Cheers All? Nope. So if there were no osmotic pressures there would still be blistering below the waterline??? Cheers |
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Flying Tadpole wrote: Nav wrote: Flying Tadpole wrote: Nav wrote: Flying Tadpole wrote: katysails wrote: MC snorted: Nah, I believe his boat is on a fresh water lake. Good one! LOL Another one who doesn't know what they're talking about when it comes to the Great Lakes.... I'd fire up antoher verse of Edmund Fitzgerald, but it's far too good and far too serious for this forum... You missed the pun too? You must be tired! Your salty pun was just too deep for me. Now that I've gone back and looked at it again, I wish I hadn't... Even a poor pun is better than no fun! Fun? FUN?? What do you think you're doing??? Have you learnt _nothing_ from your time on this newsgroup???? Actaully a few things but not having fun was not among them -despite the CN rant. You? Cheers |
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Nav wrote: Flying Tadpole wrote: Nav wrote: Flying Tadpole wrote: Nav wrote: Flying Tadpole wrote: katysails wrote: MC snorted: Nah, I believe his boat is on a fresh water lake. Good one! LOL Another one who doesn't know what they're talking about when it comes to the Great Lakes.... I'd fire up antoher verse of Edmund Fitzgerald, but it's far too good and far too serious for this forum... You missed the pun too? You must be tired! Your salty pun was just too deep for me. Now that I've gone back and looked at it again, I wish I hadn't... Even a poor pun is better than no fun! Fun? FUN?? What do you think you're doing??? Have you learnt _nothing_ from your time on this newsgroup???? Actaully a few things but not having fun was not among them -despite the CN rant. You? Cheers Funny you should say that? -- Flying Tadpole ------------------------- Break Away, Sail Away and putz away now at http://music.download.com/internetopera |
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OzOne wrote: On Wed, 30 Jun 2004 16:38:09 +1200, Nav scribbled thusly: OzOne wrote: On Wed, 30 Jun 2004 13:04:09 +1200, Nav scribbled thusly: OzOne wrote: On Wed, 30 Jun 2004 12:50:54 +1200, Nav scribbled thusly: OK so is there a big difference in viscosity? Cheers Nah. bugger all...but there is a diference. So you'll accept it's all in the osmotic pressure? Cheers All? Nope. So if there were no osmotic pressures there would still be blistering below the waterline??? Cheers I believe so. Beleif is wonderful but how so -enquiring minds want to know! Cheers |
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Flying Tadpole wrote: Nav wrote: Flying Tadpole wrote: Nav wrote: Flying Tadpole wrote: Nav wrote: Flying Tadpole wrote: katysails wrote: MC snorted: Nah, I believe his boat is on a fresh water lake. Good one! LOL Another one who doesn't know what they're talking about when it comes to the Great Lakes.... I'd fire up antoher verse of Edmund Fitzgerald, but it's far too good and far too serious for this forum... You missed the pun too? You must be tired! Your salty pun was just too deep for me. Now that I've gone back and looked at it again, I wish I hadn't... Even a poor pun is better than no fun! Fun? FUN?? What do you think you're doing??? Have you learnt _nothing_ from your time on this newsgroup???? Actaully a few things but not having fun was not among them -despite the CN rant. You? Cheers Funny you should say that? Well it tickles your fancy doesn't it? Cheers |
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OzOne wrote:
On Tue, 29 Jun 2004 10:16:39 -0400, Martin Baxter scribbled thusly: Thinner? You have some viscosity data to back this up? Yep http://www.engineeringtoolbox.com/21_397.html Hmm.... Fresh water @60F, 1.13 Centistokes, sea water @? 1.15 cSt, looks like fresh water is in fact thinner? Pretty small difference though, plus a huge variation with temperature, surely this is not the explanation? Instead of the insipid one word repartee, why not be a little less obtuse and simply provide us with your explanation for the problem at hand? Cheers Marty More likely fresh water exhibits a higher osmotic pressure because the difference in water concentration is greater in fresh than brine. (osmotic pressure being proportional to the differences in concentration on either side of the membrane) Oz1...of the 3 twins. I welcome you to crackerbox palace,We've been expecting you. |
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OzOne wrote:
On Wed, 30 Jun 2004 06:42:43 -0400, Martin Baxter scribbled thusly: OzOne wrote: The "thinner" water is able to permeate smaller viods and set up the initial reactions for the beginnings of true osmosis? I'm not an expert, just an interested bystander. Of course you do realize that while molecular size has something to do with viscosity, molecular shape and charge distribution play a much larger role? Not being a chemist I don't know if there is a difference between the H20 molecules in fresh and salt water, hell maybe the Na and Cl ions somehow bind to the porosities of the gel coat and tend to "clog" them thus slowing the process. Just another interested bystander: Cheers Marty |
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OzOne wrote:
The "thinner" water is able to permeate smaller viods and set up the initial reactions for the beginnings of true osmosis? I'm not an expert, just an interested bystander. I'm not an expert either... but it seems to me that the vapor pressure would have more to do with it than viscosity. Of course, if you want *real* answer, just ask Navvie... DSK |
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OzOne wrote: On Wed, 30 Jun 2004 17:00:04 +1200, Nav scribbled thusly: OzOne wrote: On Wed, 30 Jun 2004 16:38:09 +1200, Nav scribbled thusly: OzOne wrote: On Wed, 30 Jun 2004 13:04:09 +1200, Nav scribbled thusly: OzOne wrote: On Wed, 30 Jun 2004 12:50:54 +1200, Nav scribbled thusly: OK so is there a big difference in viscosity? Cheers Nah. bugger all...but there is a diference. So you'll accept it's all in the osmotic pressure? Cheers All? Nope. So if there were no osmotic pressures there would still be blistering below the waterline??? Cheers I believe so. Beleif is wonderful but how so -enquiring minds want to know! Cheers Actually Nav, without the osmotic pressure there would probably NOT be blistering below the waterline. Water would still penetrate the gelcoat, react with the chemicals in the resins and provide the circumstances for osmosis, but if the pressure didn't exist then thers wouldn't be enough force built up to produce the blister. Yes, I'd say that's right 'cos I've rarely seen blisters above the water line... Cheers |
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OzOne wrote: On Wed, 30 Jun 2004 15:35:01 +1000, OzOne scribbled thusly: Actually Nav, without the osmotic pressure there would probably NOT be blistering below the waterline. Water would still penetrate the gelcoat, react with the chemicals in the resins and provide the circumstances for osmosis, but if the pressure didn't exist then thers wouldn't be enough force built up to produce the blister. Oz1...of the 3 twins. I welcome you to crackerbox palace,We've been expecting you. Then again, does the initial reaction of the water with the agents in the resin produce enough gas or other force to initiate a blister.....I don't know. Do you? This question was solved in 1990's I think. Only three factors are needed, unpolymerised monomers, water and a void. If the void is not spherical (i.e. dry glass fibers) the blister risk is greater. All resins contain about 5% free monomers etc. These dissolve in the water (all resisn are water permeable to some extent) and I estimate that at 25% solute in water within the polymer void that the osmotic pressure could be about 100 psi. This pressure then starts delamination due to the law of Laplace and the limited tensile (adhesions) strength of the polmer. The resin (or gel layer) then start to peel from the glass fibers and grows rapidly from then on... The process is worsened by the leaching of resin by the water too. Cheers |
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It's mainly water vapour that penetrates...
Cheers OzOne wrote: On Wed, 30 Jun 2004 06:42:43 -0400, Martin Baxter scribbled thusly: OzOne wrote: On Tue, 29 Jun 2004 10:16:39 -0400, Martin Baxter scribbled thusly: Thinner? You have some viscosity data to back this up? Yep http://www.engineeringtoolbox.com/21_397.html Hmm.... Fresh water @60F, 1.13 Centistokes, sea water @? 1.15 cSt, looks like fresh water is in fact thinner? Pretty small difference though, plus a huge variation with temperature, surely this is not the explanation? Instead of the insipid one word repartee, why not be a little less obtuse and simply provide us with your explanation for the problem at hand? Cheers Marty The "thinner" water is able to permeate smaller viods and set up the initial reactions for the beginnings of true osmosis? I'm not an expert, just an interested bystander. Oz1...of the 3 twins. I welcome you to crackerbox palace,We've been expecting you. |
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