|
Source for Sunbrella
The US Army tested clothing fabric color relative to heat gain and found --
surprise, surprise -- dark colors had more heat gain. Maybe biminis are different from clothing in terms of heat transfer. Sorry Rosie. I stand by my emperical experience. I have been in raftups during very hot summer days. Moving between a boat with black canvas, burgundy (ours), boat blue, and cadet gray (pretty light). I could not tell any difference. Not to say that there was not any, but I couldn;t feel any. Doug s/v Callista "Rosalie B." wrote in message .. . x-no-archive:yes "Doug Dotson" wrote: It is somewhat counterintuative but I have never been able to notice any difference in temperature under a dark bimini vs a light color one. Well I know that a light roof on a building makes it easier to air condition. That's an accepted and proven engineering principle and one of the ways the people who don't have A/C make their houses cooler. (It also makes it significantly cooler if you run water over the roof which is a possibility for a deck, but probably not for a bimini) I know the deck that is darker color is hotter on bare feet and indeed, I know to walk through an asphalt parking lot barefoot on a hot day by walking on the white lines that delineate the parking spaces. I know that where the stripe is on the side of the boat, we can feel the difference in temperature of the hull inside of the boat underneath of the stripe vs the light colored hull lower down. People have told me that a dark colored hull is hotter inside than a light colored hull. So while I don't know that you'd be able to tell the difference without some kind of actual thermometer reading, I'm pretty sure that there is a difference. How much it is would have to be determined by some kind of controlled experiment which 'noticing' isn't. The transference of principles of cooling from land to boats is also seen when people have a sun shade over top of the deck and bimini- similar to the cooling effect where people have a whole attic fan which brings cooler air in on the top of the living space. A charter captain told me that she had a light bimini because the folks that chartered the boat wanted to see all the light they could, especially in the winter. But that if she had her preference she'd like to make the cockpit a cool dark hole, shaded from the sun. I want to be shaded from the sun, I just don't need it to be dark. "Rosalie B." wrote in message .. . x-no-archive:yes "Doug Dotson" wrote: Hey, hey! Our whole boat is done in Burgundy. Pacific Blue is falling out of favor around here (know popularly as Boat Blue). Captain Navy has been most popular color around here for the last few years, with burgundy, tan, and green close behind. Doug s/v Callista Our boat is in the color known as Black Cherry in the catalogs, which is maroon or burgundy. That's because we have a maroon stripe. I don't care for the tan. I like the aqua and that would be my choice maybe if we didn't have a boat with a red type stripe. I totally hate black because it becomes a rusty brown, and I don't like brown either. We used regular damask (double woven) upholstery fabric which we got from a place that was going out of business to do the cushions inside the boat. This is not a shiny satiny fabric - it's a very tough fabric with a double woven design in it. I see no reason to pay for Sunbrella for that - indoor or outdoor. We used plastic like fabric on the backsides because it was significantly cheaper, and that's the way the original cushions were done. (The original cushions were IMHO a horrible tweed) We also bought Sunbrella at this place which was bolt ends and seconds, and have used it for things like hatch covers, winch covers, dinghy motor covers etc where the fact that the waterproofing isn't as reliable doesn't matter as much. When we had the bimini made, it was made of Stamoid and we like it very much although all the needle holes tend to leak, so you can't make mistakes sewing it up. I asked whether I could have a light colored bimini to reflect the sun and was told that I should not do that because it would get dirty and the dark colors were cooler anyway. I totally don't believe that dark colors are cooler, and the Stamoid is easy to wash off. I think the Sunbrella people tell folks that the dark colors are better for biminis, but I read somewhere that dark colors protect better against UV for the sail covers and the edges of the furling headsails etc, so maybe that's what they are talking about. "Steve" wrote in message ... Yah! I been watching for Pacific Blue #4601 or #6001 on eBay, but I must have missed out on that one.. Most of the colors I have seen are those odd colors, like Burgundy, etc. I'm kinda committed to the Pacific Blue because I had several yards of it already and I made the sleeve for the furled head sail already.. So far this price is the best I have found for what I need and the fact that their minimum order is low and free shipping.. For the other poster concerned about the type; this site advertises using the Sunbrella logo and lists all that product by the the standard color numbers that I find on the actual Sunbrella site. Steve s/v Good Intentions grandma Rosalie grandma Rosalie |
Source for Sunbrella
I believe that is true for clothing, don't need the Army to tell
anybody that. What this is related to is the temperature in the shade provided by something like a bimini where it is well open to air circulation. Doug s/v Callista "JAXAshby" wrote in message ... The US Army tested clothing fabric color relative to heat gain and found -- surprise, surprise -- dark colors had more heat gain. Maybe biminis are different from clothing in terms of heat transfer. Sorry Rosie. I stand by my emperical experience. I have been in raftups during very hot summer days. Moving between a boat with black canvas, burgundy (ours), boat blue, and cadet gray (pretty light). I could not tell any difference. Not to say that there was not any, but I couldn;t feel any. Doug s/v Callista "Rosalie B." wrote in message .. . x-no-archive:yes "Doug Dotson" wrote: It is somewhat counterintuative but I have never been able to notice any difference in temperature under a dark bimini vs a light color one. Well I know that a light roof on a building makes it easier to air condition. That's an accepted and proven engineering principle and one of the ways the people who don't have A/C make their houses cooler. (It also makes it significantly cooler if you run water over the roof which is a possibility for a deck, but probably not for a bimini) I know the deck that is darker color is hotter on bare feet and indeed, I know to walk through an asphalt parking lot barefoot on a hot day by walking on the white lines that delineate the parking spaces. I know that where the stripe is on the side of the boat, we can feel the difference in temperature of the hull inside of the boat underneath of the stripe vs the light colored hull lower down. People have told me that a dark colored hull is hotter inside than a light colored hull. So while I don't know that you'd be able to tell the difference without some kind of actual thermometer reading, I'm pretty sure that there is a difference. How much it is would have to be determined by some kind of controlled experiment which 'noticing' isn't. The transference of principles of cooling from land to boats is also seen when people have a sun shade over top of the deck and bimini- similar to the cooling effect where people have a whole attic fan which brings cooler air in on the top of the living space. A charter captain told me that she had a light bimini because the folks that chartered the boat wanted to see all the light they could, especially in the winter. But that if she had her preference she'd like to make the cockpit a cool dark hole, shaded from the sun. I want to be shaded from the sun, I just don't need it to be dark. "Rosalie B." wrote in message .. . x-no-archive:yes "Doug Dotson" wrote: Hey, hey! Our whole boat is done in Burgundy. Pacific Blue is falling out of favor around here (know popularly as Boat Blue). Captain Navy has been most popular color around here for the last few years, with burgundy, tan, and green close behind. Doug s/v Callista Our boat is in the color known as Black Cherry in the catalogs, which is maroon or burgundy. That's because we have a maroon stripe. I don't care for the tan. I like the aqua and that would be my choice maybe if we didn't have a boat with a red type stripe. I totally hate black because it becomes a rusty brown, and I don't like brown either. We used regular damask (double woven) upholstery fabric which we got from a place that was going out of business to do the cushions inside the boat. This is not a shiny satiny fabric - it's a very tough fabric with a double woven design in it. I see no reason to pay for Sunbrella for that - indoor or outdoor. We used plastic like fabric on the backsides because it was significantly cheaper, and that's the way the original cushions were done. (The original cushions were IMHO a horrible tweed) We also bought Sunbrella at this place which was bolt ends and seconds, and have used it for things like hatch covers, winch covers, dinghy motor covers etc where the fact that the waterproofing isn't as reliable doesn't matter as much. When we had the bimini made, it was made of Stamoid and we like it very much although all the needle holes tend to leak, so you can't make mistakes sewing it up. I asked whether I could have a light colored bimini to reflect the sun and was told that I should not do that because it would get dirty and the dark colors were cooler anyway. I totally don't believe that dark colors are cooler, and the Stamoid is easy to wash off. I think the Sunbrella people tell folks that the dark colors are better for biminis, but I read somewhere that dark colors protect better against UV for the sail covers and the edges of the furling headsails etc, so maybe that's what they are talking about. "Steve" wrote in message ... Yah! I been watching for Pacific Blue #4601 or #6001 on eBay, but I must have missed out on that one.. Most of the colors I have seen are those odd colors, like Burgundy, etc. I'm kinda committed to the Pacific Blue because I had several yards of it already and I made the sleeve for the furled head sail already.. So far this price is the best I have found for what I need and the fact that their minimum order is low and free shipping.. For the other poster concerned about the type; this site advertises using the Sunbrella logo and lists all that product by the the standard color numbers that I find on the actual Sunbrella site. Steve s/v Good Intentions grandma Rosalie grandma Rosalie |
Source for Sunbrella
"Doug Dotson" wrote:
Sorry Rosie. I stand by my emperical experience. I have been in raftups during very hot summer days. Moving between a boat with black canvas, burgundy (ours), boat blue, and cadet gray (pretty light). I could not tell any difference. Not to say that there was not any, but I couldn;t feel any. I think it depends a bit on how much wind there is (you seem to indicate that there was some). If there is a breeze the heat doesn't accumulate. You would have to be able to measure the heat with no ventilation in order to be able to feel the difference. Or you may just not be very sensitive. Anything that keeps the sun off will be cooler underneath. But I know that having A/C in a building with a dark roof will be more expensive to run to the same temp than a similar building with a light roof and if you really want to bring the energy use down, run water over the light colored roof. Also a building with a dark roof heats up in the summer more than a building with a light colored roof. I do not see how a bimini would be any different, absent lack of thru ventilation. Doug s/v Callista "Rosalie B." wrote in message .. . x-no-archive:yes "Doug Dotson" wrote: It is somewhat counterintuative but I have never been able to notice any difference in temperature under a dark bimini vs a light color one. Well I know that a light roof on a building makes it easier to air condition. That's an accepted and proven engineering principle and one of the ways the people who don't have A/C make their houses cooler. (It also makes it significantly cooler if you run water over the roof which is a possibility for a deck, but probably not for a bimini) I know the deck that is darker color is hotter on bare feet and indeed, I know to walk through an asphalt parking lot barefoot on a hot day by walking on the white lines that delineate the parking spaces. I know that where the stripe is on the side of the boat, we can feel the difference in temperature of the hull inside of the boat underneath of the stripe vs the light colored hull lower down. People have told me that a dark colored hull is hotter inside than a light colored hull. So while I don't know that you'd be able to tell the difference without some kind of actual thermometer reading, I'm pretty sure that there is a difference. How much it is would have to be determined by some kind of controlled experiment which 'noticing' isn't. The transference of principles of cooling from land to boats is also seen when people have a sun shade over top of the deck and bimini- similar to the cooling effect where people have a whole attic fan which brings cooler air in on the top of the living space. A charter captain told me that she had a light bimini because the folks that chartered the boat wanted to see all the light they could, especially in the winter. But that if she had her preference she'd like to make the cockpit a cool dark hole, shaded from the sun. I want to be shaded from the sun, I just don't need it to be dark. "Rosalie B." wrote in message .. . x-no-archive:yes "Doug Dotson" wrote: Hey, hey! Our whole boat is done in Burgundy. Pacific Blue is falling out of favor around here (know popularly as Boat Blue). Captain Navy has been most popular color around here for the last few years, with burgundy, tan, and green close behind. Doug s/v Callista Our boat is in the color known as Black Cherry in the catalogs, which is maroon or burgundy. That's because we have a maroon stripe. I don't care for the tan. I like the aqua and that would be my choice maybe if we didn't have a boat with a red type stripe. I totally hate black because it becomes a rusty brown, and I don't like brown either. We used regular damask (double woven) upholstery fabric which we got from a place that was going out of business to do the cushions inside the boat. This is not a shiny satiny fabric - it's a very tough fabric with a double woven design in it. I see no reason to pay for Sunbrella for that - indoor or outdoor. We used plastic like fabric on the backsides because it was significantly cheaper, and that's the way the original cushions were done. (The original cushions were IMHO a horrible tweed) We also bought Sunbrella at this place which was bolt ends and seconds, and have used it for things like hatch covers, winch covers, dinghy motor covers etc where the fact that the waterproofing isn't as reliable doesn't matter as much. When we had the bimini made, it was made of Stamoid and we like it very much although all the needle holes tend to leak, so you can't make mistakes sewing it up. I asked whether I could have a light colored bimini to reflect the sun and was told that I should not do that because it would get dirty and the dark colors were cooler anyway. I totally don't believe that dark colors are cooler, and the Stamoid is easy to wash off. I think the Sunbrella people tell folks that the dark colors are better for biminis, but I read somewhere that dark colors protect better against UV for the sail covers and the edges of the furling headsails etc, so maybe that's what they are talking about. "Steve" wrote in message ... Yah! I been watching for Pacific Blue #4601 or #6001 on eBay, but I must have missed out on that one.. Most of the colors I have seen are those odd colors, like Burgundy, etc. I'm kinda committed to the Pacific Blue because I had several yards of it already and I made the sleeve for the furled head sail already.. So far this price is the best I have found for what I need and the fact that their minimum order is low and free shipping.. For the other poster concerned about the type; this site advertises using the Sunbrella logo and lists all that product by the the standard color numbers that I find on the actual Sunbrella site. Steve s/v Good Intentions grandma Rosalie grandma Rosalie grandma Rosalie |
Source for Sunbrella
"Rosalie B." wrote in message ... "Doug Dotson" wrote: Sorry Rosie. I stand by my emperical experience. I have been in raftups during very hot summer days. Moving between a boat with black canvas, burgundy (ours), boat blue, and cadet gray (pretty light). I could not tell any difference. Not to say that there was not any, but I couldn;t feel any. I think it depends a bit on how much wind there is (you seem to indicate that there was some). If there is a breeze the heat doesn't accumulate. You would have to be able to measure the heat with no ventilation in order to be able to feel the difference. Or you may just not be very sensitive. But this is exactly the typical situation. A bimini as shade. The situation with an enclosure is different. Although I think that in an enclosure with limited ventilation the darker the color, the faster it will heat up. I suspect the actual temperature will not be that much different. We just installed a full enclosere last week. It was very light gray. Hotter than hell within minutes. I doubt that it could be much different with darker canvas. Matter of fact, much of the enclosure was clear. Anything that keeps the sun off will be cooler underneath. But I know that having A/C in a building with a dark roof will be more expensive to run to the same temp than a similar building with a light roof and if you really want to bring the energy use down, run water over the light colored roof. Also a building with a dark roof heats up in the summer more than a building with a light colored roof. I do not see how a bimini would be any different, absent lack of thru ventilation. Correct. But this is not analagous. I believe we are talking about the shade under a canopy open on the sides. Even with little wind, any accumulated heat underneath will flow out a few inches below the canopy. Doug s/v Callista "Rosalie B." wrote in message .. . x-no-archive:yes "Doug Dotson" wrote: It is somewhat counterintuative but I have never been able to notice any difference in temperature under a dark bimini vs a light color one. Well I know that a light roof on a building makes it easier to air condition. That's an accepted and proven engineering principle and one of the ways the people who don't have A/C make their houses cooler. (It also makes it significantly cooler if you run water over the roof which is a possibility for a deck, but probably not for a bimini) I know the deck that is darker color is hotter on bare feet and indeed, I know to walk through an asphalt parking lot barefoot on a hot day by walking on the white lines that delineate the parking spaces. I know that where the stripe is on the side of the boat, we can feel the difference in temperature of the hull inside of the boat underneath of the stripe vs the light colored hull lower down. People have told me that a dark colored hull is hotter inside than a light colored hull. So while I don't know that you'd be able to tell the difference without some kind of actual thermometer reading, I'm pretty sure that there is a difference. How much it is would have to be determined by some kind of controlled experiment which 'noticing' isn't. The transference of principles of cooling from land to boats is also seen when people have a sun shade over top of the deck and bimini- similar to the cooling effect where people have a whole attic fan which brings cooler air in on the top of the living space. A charter captain told me that she had a light bimini because the folks that chartered the boat wanted to see all the light they could, especially in the winter. But that if she had her preference she'd like to make the cockpit a cool dark hole, shaded from the sun. I want to be shaded from the sun, I just don't need it to be dark. "Rosalie B." wrote in message .. . x-no-archive:yes "Doug Dotson" wrote: Hey, hey! Our whole boat is done in Burgundy. Pacific Blue is falling out of favor around here (know popularly as Boat Blue). Captain Navy has been most popular color around here for the last few years, with burgundy, tan, and green close behind. Doug s/v Callista Our boat is in the color known as Black Cherry in the catalogs, which is maroon or burgundy. That's because we have a maroon stripe. I don't care for the tan. I like the aqua and that would be my choice maybe if we didn't have a boat with a red type stripe. I totally hate black because it becomes a rusty brown, and I don't like brown either. We used regular damask (double woven) upholstery fabric which we got from a place that was going out of business to do the cushions inside the boat. This is not a shiny satiny fabric - it's a very tough fabric with a double woven design in it. I see no reason to pay for Sunbrella for that - indoor or outdoor. We used plastic like fabric on the backsides because it was significantly cheaper, and that's the way the original cushions were done. (The original cushions were IMHO a horrible tweed) We also bought Sunbrella at this place which was bolt ends and seconds, and have used it for things like hatch covers, winch covers, dinghy motor covers etc where the fact that the waterproofing isn't as reliable doesn't matter as much. When we had the bimini made, it was made of Stamoid and we like it very much although all the needle holes tend to leak, so you can't make mistakes sewing it up. I asked whether I could have a light colored bimini to reflect the sun and was told that I should not do that because it would get dirty and the dark colors were cooler anyway. I totally don't believe that dark colors are cooler, and the Stamoid is easy to wash off. I think the Sunbrella people tell folks that the dark colors are better for biminis, but I read somewhere that dark colors protect better against UV for the sail covers and the edges of the furling headsails etc, so maybe that's what they are talking about. "Steve" wrote in message ... Yah! I been watching for Pacific Blue #4601 or #6001 on eBay, but I must have missed out on that one.. Most of the colors I have seen are those odd colors, like Burgundy, etc. I'm kinda committed to the Pacific Blue because I had several yards of it already and I made the sleeve for the furled head sail already.. So far this price is the best I have found for what I need and the fact that their minimum order is low and free shipping.. For the other poster concerned about the type; this site advertises using the Sunbrella logo and lists all that product by the the standard color numbers that I find on the actual Sunbrella site. Steve s/v Good Intentions grandma Rosalie grandma Rosalie grandma Rosalie |
Source for Sunbrella
"Doug Dotson" wrote:
"Rosalie B." wrote in message .. . "Doug Dotson" wrote: Sorry Rosie. I stand by my emperical experience. I have been in raftups during very hot summer days. Moving between a boat with black canvas, burgundy (ours), boat blue, and cadet gray (pretty light). I could not tell any difference. Not to say that there was not any, but I couldn;t feel any. I think it depends a bit on how much wind there is (you seem to indicate that there was some). If there is a breeze the heat doesn't accumulate. You would have to be able to measure the heat with no ventilation in order to be able to feel the difference. Or you may just not be very sensitive. But this is exactly the typical situation. A bimini as shade. The situation with an enclosure is different. Although I think that in an enclosure with limited ventilation the darker the color, the faster it will heat up. I suspect the actual temperature will not be that much different. We just installed a full enclosere last week. It was very light gray. Hotter than hell within minutes. I doubt that it could be much different with darker canvas. Matter of fact, much of the enclosure was clear. If the enclosure is clear, then it isn't shading the cockpit unless the sun is directly overhead. And heating up faster is what we want to avoid. If it heats up more slowly, then the heat can disperse better. It may be true that it will get no hotter than a certain temperature - but slowing the accumulations of heat is an achievable goal. This winter, the boat was at the dock and faced east. The rising sun shown through the dodger down into the aft cabin and heated it up. So I hung a towel down over the hatch. This blocked the sun and made the cabin comfortable all day. Anything that keeps the sun off will be cooler underneath. But I know that having A/C in a building with a dark roof will be more expensive to run to the same temp than a similar building with a light roof and if you really want to bring the energy use down, run water over the light colored roof. Also a building with a dark roof heats up in the summer more than a building with a light colored roof. I do not see how a bimini would be any different, absent lack of thru ventilation. Correct. But this is not analagous. I believe we are talking about the shade under a canopy open on the sides. Even with little wind, any accumulated heat underneath will flow out a few inches below the canopy. I think it is quite analogous. I am talking about a bimini with sides which can be rolled up or left down. In the winter when it is cold, we leave the sides zipped up and the clear plastic enclosure is like a sun room - the sun heats it up very nicely and we can be inside in our shirt sleeves while those folks with aft cockpits and no bimini or only a minimal one are in their foulies looking very miserable. In the heat, we have at least one side (the back) stationary (we can remove it, but then if it rains, the enclosure is open at the back), and two pieces on each side of the dodger that aren't rolled up. If we are sailing (or motoring into the wind), there is airflow unless the wind is directly from the rear. If we are at anchor or at the dock, we may not have any airflow. The heat may flow out below the canopy but I will be miserable, and that little outflow won't really help me a bit. Actually, if it is really hot and the boat is stationary, a canvas tent over the boom helps a lot to keep the cockpit and boat cooler. I see no reason to think that the principles of heat transfer which apply in other situations will not apply also to boats and biminis. The fact that it will get hot under a bimini in the direct sun even if it is light colored doesn't't disprove the principle that a lighter color will reflect more of the light than a darker color. The absorbed light becomes heat. grandma Rosalie |
Source for Sunbrella
I believe that is true for clothing, don't need the Army to tell
anybody that. What this is related to is the temperature in the shade provided by something like a bimini where it is well open to air circulation. Huh???? you mean you are trying to say that heat gain temp under cloth is not heat gain temp under cloth if it is stretched across aluminum or stainless steel piping? Dougies, do you understand what the term temperature means? Doug |
Canvas colors
A couple of notes:
The coolest color is white, because it reflects more sunlight than any other. Matter of fact, in the color industry, they use pure titanium dioxide pigment (white) as the 100% reflectance standard. The coolest canvas would be white. Black or dark colors basically act as solar collectors. If it's just a bimini, you might notice a difference or not. You'll SURE notice a difference in how dirty the white gets though! OTOH, the most UV stable color is black. That's because the pigment used to make it black is carbon black... degraded about as far as it can be. That's why I use black dock lines, etc. Yea, they do get hotter which will degrade them a bit faster, but UV is what really kills synthetics. Oh yea, those "reflective" "silver" tarps aren't. The pigment is just aluminum powder, and acts just like any dark color. If you want something reflective, get metallized mylar like they use in space blankets. Kinda impractical though. -- Keith __ The main reason Santa is so jolly is because he knows where all the bad girls live. "Rosalie B." wrote in message ... "Doug Dotson" wrote: "Rosalie B." wrote in message .. . "Doug Dotson" wrote: Sorry Rosie. I stand by my emperical experience. I have been in raftups during very hot summer days. Moving between a boat with black canvas, burgundy (ours), boat blue, and cadet gray (pretty light). I could not tell any difference. Not to say that there was not any, but I couldn;t feel any. I think it depends a bit on how much wind there is (you seem to indicate that there was some). If there is a breeze the heat doesn't accumulate. You would have to be able to measure the heat with no ventilation in order to be able to feel the difference. Or you may just not be very sensitive. But this is exactly the typical situation. A bimini as shade. The situation with an enclosure is different. Although I think that in an enclosure with limited ventilation the darker the color, the faster it will heat up. I suspect the actual temperature will not be that much different. We just installed a full enclosere last week. It was very light gray. Hotter than hell within minutes. I doubt that it could be much different with darker canvas. Matter of fact, much of the enclosure was clear. If the enclosure is clear, then it isn't shading the cockpit unless the sun is directly overhead. And heating up faster is what we want to avoid. If it heats up more slowly, then the heat can disperse better. It may be true that it will get no hotter than a certain temperature - but slowing the accumulations of heat is an achievable goal. This winter, the boat was at the dock and faced east. The rising sun shown through the dodger down into the aft cabin and heated it up. So I hung a towel down over the hatch. This blocked the sun and made the cabin comfortable all day. Anything that keeps the sun off will be cooler underneath. But I know that having A/C in a building with a dark roof will be more expensive to run to the same temp than a similar building with a light roof and if you really want to bring the energy use down, run water over the light colored roof. Also a building with a dark roof heats up in the summer more than a building with a light colored roof. I do not see how a bimini would be any different, absent lack of thru ventilation. Correct. But this is not analagous. I believe we are talking about the shade under a canopy open on the sides. Even with little wind, any accumulated heat underneath will flow out a few inches below the canopy. I think it is quite analogous. I am talking about a bimini with sides which can be rolled up or left down. In the winter when it is cold, we leave the sides zipped up and the clear plastic enclosure is like a sun room - the sun heats it up very nicely and we can be inside in our shirt sleeves while those folks with aft cockpits and no bimini or only a minimal one are in their foulies looking very miserable. In the heat, we have at least one side (the back) stationary (we can remove it, but then if it rains, the enclosure is open at the back), and two pieces on each side of the dodger that aren't rolled up. If we are sailing (or motoring into the wind), there is airflow unless the wind is directly from the rear. If we are at anchor or at the dock, we may not have any airflow. The heat may flow out below the canopy but I will be miserable, and that little outflow won't really help me a bit. Actually, if it is really hot and the boat is stationary, a canvas tent over the boom helps a lot to keep the cockpit and boat cooler. I see no reason to think that the principles of heat transfer which apply in other situations will not apply also to boats and biminis. The fact that it will get hot under a bimini in the direct sun even if it is light colored doesn't't disprove the principle that a lighter color will reflect more of the light than a darker color. The absorbed light becomes heat. grandma Rosalie |
Source for Sunbrella
|
Canvas colors
"Keith" wrote:
A couple of notes: The coolest color is white, because it reflects more sunlight than any other. Matter of fact, in the color industry, they use pure titanium dioxide pigment (white) as the 100% reflectance standard. The coolest canvas would be white. Black or dark colors basically act as solar collectors. If it's just a bimini, you might notice a difference or not. You'll SURE notice a difference in how dirty the white gets though! That's why we don't have pure white, but a kind of cream. And since it is stamoid, it is easy to wash. The only real trouble we have with dirt is the thread and velcro which gets mildewed and doesn't ever look clean. OTOH, the most UV stable color is black. That's because the pigment used to make it black is carbon black... degraded about as far as it can be. That's why I use black dock lines, etc. Yea, they do get hotter which will degrade them a bit faster, but UV is what really kills synthetics. I guess that's also why they recommend dark colors for sail covers. Oh yea, those "reflective" "silver" tarps aren't. The pigment is just aluminum powder, and acts just like any dark color. If you want something reflective, get metallized mylar like they use in space blankets. Kinda impractical though. grandma Rosalie |
Canvas colors
Probably the best compromise would be "seagull dropping grey" with white
flecks? :-) -- Glenn Ashmore I'm building a 45' cutter in strip/composite. Watch my progress (or lack there of) at: http://www.rutuonline.com Shameless Commercial Division: http://www.spade-anchor-us.com |
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