Home |
Search |
Today's Posts |
#21
![]()
posted to rec.boats.cruising
|
|||
|
|||
![]()
Rick Morel wrote:
On Thu, 15 Feb 2007 23:24:19 GMT, Don W wrote: Hey, I know that the v-berth is unusable for sleeping at sea in anything but benign conditions anyway. Ask me how I know ;-) Might as well use it as a big (well... sorta) walk in closet. Don't have to ask. I know :-) As an aside, my ex could take anything short period, in shallow water. Offshore she got very seasick. To the point of considering her flying to the next from-offshore destination. She found a fix - stay in the forward stateroom and sleep on the vee-berth. It was the sloooow up and down that got to her; no problem with the FAST up and down. Wow, who would have thought. Myself I had a problem with the weightlessness, and then crashing back into the mattress. It kept waking me up ;-) Vee-berth will be our "bedroom" cause it's the only double. Settee berth will be the single off-watch berth when needed. With added, what are they called, rod and canvas thing that comes up and attaches so you don't roll out. "Lee cloths"? As far as making up the settee, which is what we do on the Irwin right now, we'll see. The problem is that the aft cabin is pretty low, and my wife can not seem to remember to not bang her head on it for more than two weeks at a time. Since she's slightly claustrophobic anyway, but doesn't seem to mind folding the bedding, I figure that we've got _two_ walk in closets, and no eating after bedtime. Of course, if you just want to catch a quick nap, there is the qtr-berth on the other side of the aisle from the settee, and its always available. One reason we passed on the S2 30 center cockpit. The other is that one had to sit on the shelf of the tiny bathtub and hunker over to take a shower. As I recall, lots of room between the dinette and settee - a friend has an Irwin 37. Folding table at the settee? "Dinette" for two? Leave the bed made? Just rambling.... Our Irwin is a Citation 38, and its got a really stupid setup for the table (Sorry Ted, but its true.) Our C27 seats four comfortably for dinner, but you can't even get four placemats on the IC38 table ![]() redesign it, where it is big enough for six and quickly and easily folds up around the mast out of the way. I did some checking. Princess 3-burner Marine Stove, which seems typical. 1 simmer (550 watt) and 2 high speed (1100 watt) burners 1250 watt bake element 1300 watt broiler element So less than I was thinking. Dang, I do remember a factory printed placard next to my friend's stove listing combinations of burners/oven. But then the stove in that monster was more of a home type! Anyway it's 1,876 BTU, 3,753 BTU and 4,265 BTU respectively, leaving out the broiler and assuming 100% electric to heat conversion. Doing the conversion propane, with 5,000 BTU and 8,000 BTU burners, and 6500-16250 BTU oven (from checking) works out to 1,465 W, 2,344 W, 1,905-4,762 W output respectively. Okay, so looking at the marine electric vs. propane, and factoring in the home electric, it seems the marine electric is designed more to fit the genset and shore power socket. Specs on home electric stoves are harder to find. In any event, electric should give better heat tranfer to the pot, no airpace under to radiate heat, and one seldom uses a propane stove full blast except to quickly bring to a boil. Where am I going with this? Noplace, really. It's just information. No doubt propane is nicer to cook with. I'm just trying to eliminate one whole system from the boat, and regain some usable counterspace at the same time. BTW, the wattages I wrote up above came right off of the placards in our kitchen 5 minutes before I posted. I've still got the post-it with the notes I jotted down while checking them all. Note that the entire cooking time is only 1/4 hour at 1/3 gal/hr so you use a little over a pint of fuel to cook breakfast. At $5/gallon this works out to 72 cents for fuel. The potato probably cost that much! I could go through lunch and dinner, but for us they would typically be even less, since the griddle and coffee maker are not in use. Often for dinner we have a salad, or heat up homemade soup in the microwave. Lunches are typically sandwiches, or a salad or re-heated soup. After breakfast is cooked, the genset can power the watermaker and the hot water heater while we eat and do dishes. Our water heater is a 11 gallon Force 10 which draws 1500W. If the watermaker draws 1000W like you say down below, we've got 500W left over (12V @ 41A!) to charge the batteries for the day. Sounds like a well thought out plan! $5 a gallon for gas? Is this what the marinas are charging these days? Wow! I'd consider dinghying in with a few jerry cans and looking for a regular auto gas station! We're paying about $2/gallon here at the gas station, but I'm assuming it will be a lot more in Turks and Caicos, the Caymans, or Martinique. Anyone have any current info? Also, I don't really expect to use anywhere near 70 Gallons per day of water, but don't really know for sure. We used 4 to 6 gallons a day. High compared to many. One of the most wasteful water things is running the hot water tap, waiting for the hot to get there. Some folks put a valve in the line and route it back to the tank until it gets hot, close the valve and turn on the hot water tap. Well, you didn't have a watermaker either, so you were trying to conserve a lot. I measured what we used at home for showers one time, and was really surprised. Something like 20+ gallons each even with the low flow shower head. I could easily see us using 30-50 GPD with the two of us, and more with guests. Okay. Let's try it this way. Cooking two meals a day (SNIP) Amazingly we came really close to the same answer for fuel burn. Must be right ;-) Oh, us engineering types :-) LOL Agreed. The aussies have some triple junction research solar cells that reach in the low 60% efficiency IIRC. Now if somebody would just start massive production to get the cost down. BTW, I had to take thermodynamics to get the degree, so I'm with you on the energy conversion losses. Entropy always wins. Agreed. I came across the following: "Today, commonly available solar panels are 12% efficient, which is four times greater than only a few years ago." and "Silicon solar cell efficiencies vary from 6% for amorphous silicon-based solar cells to 40.7% with multiple-junction research lab cells. Solar cell energy conversion efficiencies for commercially available mc-Si solar cells are around 14-16%. The highest efficiency cells have not always been the most economical -- for example a 30% efficient multijunction cell based on exotic materials such as gallium arsenide or indium selenide and produced in low volume might well cost one hundred times as much as an 8% efficient amorphous silicon cell in mass production, while only delivering about four times the electrical power." Also came across a company claiming they've got 22%, "up to 50% more", that are available now. Couldn't find a price anywhere. Their size specs show they're about 71% of the area of the others. Bottom line for us is try to find the space needed for "regular" panels. I have a source for inexpensive removals from our offshore oil industry. That is a nice source. Solar is great except for the initial cost, and that cost is coming down. Please don't get a 25 GPH watermaker, unless you plan on using at least 50 Gallons of water per day! SNIP I'm considering buying the membrane and pump(s) and constructing my own watermaker--and yes, I'm aware that the sea water membranes are quite different from freshwater ones like I have under the sink at home. It's not rocket science though, and that way when it breaks down, I'll have a clue how to go about fixing it. Lot's of stuff on the web by Brent Swain re rolling your own. No details except "buy my book". Ran across at least one web site with details. Most are high output with a pressure washer pump. Right, it's not rocket science. I'm looking at what it would take to build that ideal-for-me 3 GPH one with a 12V drive. With an engineering background you should be able to do it easily. Its just a matter of maintaining pressure and flow across the membrane. The rest is filtering and flow to keep the sludge off of the membrane. Yes, the home and seawater ones are diffenent and as I understand seawater requires about 800 PSI and a finer membrane as opposed to the home 30 or 40 PSI regular water pressure. You are correct about the pressures, but the difference is not so much that the membrane is finer, but that it is a different composition to be able to withstand the higher pressure. However, I did come across something that makes me wonder. First, PUR says "Salt Rejection: 98.4% average (96% minimum).." GE has a new home RO and says, "GE Infrastructure Water and Process Technologies has achieved a revolutionary breakthrough in the water treatment industry." 720 GPD and $400. They use salt for the TDS specs and it is, "TDS Rejection (NaCl) 90% Min, 99% Max, 93% Average." Okay. Never tasted salt or anything in those years of drinking RO from a PUR. Did taste salty at some marinas in FL (guess it was in the ground water). So taking worse case, maybe twice the salt left with the GE. How "tasty" is twice no taste? GE says the "Inlet TDS" is from 50 MG/L to 2 G/L. A quick check finds seawater is 35 G/L. Oh oh! 17.5 times the max! Is the max really the max? Or is it a convient and/or tested figure because that's the most ever expected from city and/or well water? What happens if seawater were used? Would it clog/ruin the membrane? Would it remove 1/17 or 1/X as much TDS? What is the criteria for TDS? I'm not an expert on RO, but I believe that the higher the salt concentration the higher the osmotic pressure, and therefore the higher the pressure required to reverse the osmotic process. I've done some initial research, but need to do more. The above presented really to point out one has to research things all the way, as you've done. Not very difficult these days with the internet. How I remember spending hours, even days at libraries in the past. Isn't that the truth. I used to go down to the UT engineering library to research patents on microfilm. Now you can pull them up for free off the internet. Hmmm... Another research project. If one has say 25 GPH membranes, can one run less water through them, say from a 12V pump, and get 2 or 3 or 8 or whatever GPH? Say an engine driven or AC genset driven, if you have one, high volume pump and a 12V low volume? Less efficient? Would it even work? I honestly don't understand everything I know about RO! You have to have enough pressure to reverse the natural osmosis. Basically, its pre-filtering, pressure across the membrane, and flow on the "dirty" side of the membrane to keep the "debris" moving along so as not to clog the membrane. I notice there are two RO manufacturers within 30 minutes from here. They do the BIG stuff for the oil industry, 10,000 GPD. I think I might visit one or both. Okay Rick. Next project is to research and learn everything currently known about RO watermakers. Cruise ships have some monstrous systems, and I had the opportunity to view and discuss one with the chief engineer a few years back. The requirement for generating clean water on ships goes all the way back to the water used in steam boilers. The Navy was doing it back in WWII--probably before. Our Cornado's aft deck, under the mizzen boom, had a solar "patio roof". Took up the whole aft deck and hung a bit over the sides on the aft end. 5 X 7 feet as I recall. The new owner moved them to the lifelines. He added stainless tubing and fashioned mounts so they could swing down, vertically. Seems to work. This is probably what I'll have to do with at least a couple. The other two can go on an arch over the davits. I've seen boats outfitted like that. I always wonder what's going to happen to those panels when they catch a good boarding wave over the bow, but maybe they just plan on not doing that. Psych 101. "WE'LL get used to it." Gotcha ;-) Honestly, don't pretend you're 100% in heaven. In truth you'll have to get used to it too. Well, unless your idea of comfort is a 30-day canoe trip down the Amazon. :-) Well, I'm not 100% sure that I'll like living on the sailboat and cruising although I think I will. We're going to try it in small doses for a while and see how it goes. Thanks! Yep. Been there done that. Gonna do it again!!!! Hot dawg!!!! Well, _you_ must have liked it... Speaking of there. I'm in New Iberia, LA. Middle of the state about as close as you can get to the coast without living with the gators. I saw in another post you're Texas coast. What part? Just curious. We're in Austin, but the boat is in Palacios on the northern side of Matagorda Bay. Rick Don W. |
#22
![]()
posted to rec.boats.cruising
|
|||
|
|||
![]()
Don W wrote:
Rick Morel wrote: On Thu, 15 Feb 2007 23:24:19 GMT, Don W wrote: Hey, I know that the v-berth is unusable for sleeping at sea in anything but benign conditions anyway. Ask me how I know ;-) Might as well use it as a big (well... sorta) walk in closet. Don't have to ask. I know :-) As an aside, my ex could take anything short period, in shallow water. Offshore she got very seasick. To the point of considering her flying to the next from-offshore destination. She found a fix - stay in the forward stateroom and sleep on the vee-berth. It was the sloooow up and down that got to her; no problem with the FAST up and down. Wow, who would have thought. Myself I had a problem with the weightlessness, and then crashing back into the mattress. It kept waking me up ;-) Vee-berth will be our "bedroom" cause it's the only double. Settee berth will be the single off-watch berth when needed. With added, what are they called, rod and canvas thing that comes up and attaches so you don't roll out. "Lee cloths"? As far as making up the settee, which is what we do on the Irwin right now, we'll see. The problem is that the aft cabin is pretty low, and my wife can not seem to remember to not bang her head on it for more than two weeks at a time. Since she's slightly claustrophobic anyway, but doesn't seem to mind folding the bedding, I figure that we've got _two_ walk in closets, and no eating after bedtime. Of course, if you just want to catch a quick nap, there is the qtr-berth on the other side of the aisle from the settee, and its always available. One reason we passed on the S2 30 center cockpit. The other is that one had to sit on the shelf of the tiny bathtub and hunker over to take a shower. As I recall, lots of room between the dinette and settee - a friend has an Irwin 37. Folding table at the settee? "Dinette" for two? Leave the bed made? Just rambling.... Our Irwin is a Citation 38, and its got a really stupid setup for the table (Sorry Ted, but its true.) Our C27 seats four comfortably for dinner, but you can't even get four placemats on the IC38 table ![]() of my projects is to redesign it, where it is big enough for six and quickly and easily folds up around the mast out of the way. I did some checking. Princess 3-burner Marine Stove, which seems typical. 1 simmer (550 watt) and 2 high speed (1100 watt) burners 1250 watt bake element 1300 watt broiler element So less than I was thinking. Dang, I do remember a factory printed placard next to my friend's stove listing combinations of burners/oven. But then the stove in that monster was more of a home type! Anyway it's 1,876 BTU, 3,753 BTU and 4,265 BTU respectively, leaving out the broiler and assuming 100% electric to heat conversion. Doing the conversion propane, with 5,000 BTU and 8,000 BTU burners, and 6500-16250 BTU oven (from checking) works out to 1,465 W, 2,344 W, 1,905-4,762 W output respectively. Okay, so looking at the marine electric vs. propane, and factoring in the home electric, it seems the marine electric is designed more to fit the genset and shore power socket. Specs on home electric stoves are harder to find. In any event, electric should give better heat tranfer to the pot, no airpace under to radiate heat, and one seldom uses a propane stove full blast except to quickly bring to a boil. Where am I going with this? Noplace, really. It's just information. No doubt propane is nicer to cook with. I'm just trying to eliminate one whole system from the boat, and regain some usable counterspace at the same time. BTW, the wattages I wrote up above came right off of the placards in our kitchen 5 minutes before I posted. I've still got the post-it with the notes I jotted down while checking them all. Note that the entire cooking time is only 1/4 hour at 1/3 gal/hr so you use a little over a pint of fuel to cook breakfast. At $5/gallon this works out to 72 cents for fuel. The potato probably cost that much! I could go through lunch and dinner, but for us they would typically be even less, since the griddle and coffee maker are not in use. Often for dinner we have a salad, or heat up homemade soup in the microwave. Lunches are typically sandwiches, or a salad or re-heated soup. After breakfast is cooked, the genset can power the watermaker and the hot water heater while we eat and do dishes. Our water heater is a 11 gallon Force 10 which draws 1500W. If the watermaker draws 1000W like you say down below, we've got 500W left over (12V @ 41A!) to charge the batteries for the day. Sounds like a well thought out plan! $5 a gallon for gas? Is this what the marinas are charging these days? Wow! I'd consider dinghying in with a few jerry cans and looking for a regular auto gas station! We're paying about $2/gallon here at the gas station, but I'm assuming it will be a lot more in Turks and Caicos, the Caymans, or Martinique. Anyone have any current info? Also, I don't really expect to use anywhere near 70 Gallons per day of water, but don't really know for sure. We used 4 to 6 gallons a day. High compared to many. One of the most wasteful water things is running the hot water tap, waiting for the hot to get there. Some folks put a valve in the line and route it back to the tank until it gets hot, close the valve and turn on the hot water tap. Well, you didn't have a watermaker either, so you were trying to conserve a lot. I measured what we used at home for showers one time, and was really surprised. Something like 20+ gallons each even with the low flow shower head. I could easily see us using 30-50 GPD with the two of us, and more with guests. Okay. Let's try it this way. Cooking two meals a day (SNIP) Amazingly we came really close to the same answer for fuel burn. Must be right ;-) Oh, us engineering types :-) LOL Agreed. The aussies have some triple junction research solar cells that reach in the low 60% efficiency IIRC. Now if somebody would just start massive production to get the cost down. BTW, I had to take thermodynamics to get the degree, so I'm with you on the energy conversion losses. Entropy always wins. Agreed. I came across the following: "Today, commonly available solar panels are 12% efficient, which is four times greater than only a few years ago." and "Silicon solar cell efficiencies vary from 6% for amorphous silicon-based solar cells to 40.7% with multiple-junction research lab cells. Solar cell energy conversion efficiencies for commercially available mc-Si solar cells are around 14-16%. The highest efficiency cells have not always been the most economical -- for example a 30% efficient multijunction cell based on exotic materials such as gallium arsenide or indium selenide and produced in low volume might well cost one hundred times as much as an 8% efficient amorphous silicon cell in mass production, while only delivering about four times the electrical power." Also came across a company claiming they've got 22%, "up to 50% more", that are available now. Couldn't find a price anywhere. Their size specs show they're about 71% of the area of the others. Bottom line for us is try to find the space needed for "regular" panels. I have a source for inexpensive removals from our offshore oil industry. That is a nice source. Solar is great except for the initial cost, and that cost is coming down. Please don't get a 25 GPH watermaker, unless you plan on using at least 50 Gallons of water per day! SNIP I'm considering buying the membrane and pump(s) and constructing my own watermaker--and yes, I'm aware that the sea water membranes are quite different from freshwater ones like I have under the sink at home. It's not rocket science though, and that way when it breaks down, I'll have a clue how to go about fixing it. Lot's of stuff on the web by Brent Swain re rolling your own. No details except "buy my book". Ran across at least one web site with details. Most are high output with a pressure washer pump. Right, it's not rocket science. I'm looking at what it would take to build that ideal-for-me 3 GPH one with a 12V drive. With an engineering background you should be able to do it easily. Its just a matter of maintaining pressure and flow across the membrane. The rest is filtering and flow to keep the sludge off of the membrane. Yes, the home and seawater ones are diffenent and as I understand seawater requires about 800 PSI and a finer membrane as opposed to the home 30 or 40 PSI regular water pressure. You are correct about the pressures, but the difference is not so much that the membrane is finer, but that it is a different composition to be able to withstand the higher pressure. However, I did come across something that makes me wonder. First, PUR says "Salt Rejection: 98.4% average (96% minimum).." GE has a new home RO and says, "GE Infrastructure Water and Process Technologies has achieved a revolutionary breakthrough in the water treatment industry." 720 GPD and $400. They use salt for the TDS specs and it is, "TDS Rejection (NaCl) 90% Min, 99% Max, 93% Average." Okay. Never tasted salt or anything in those years of drinking RO from a PUR. Did taste salty at some marinas in FL (guess it was in the ground water). So taking worse case, maybe twice the salt left with the GE. How "tasty" is twice no taste? GE says the "Inlet TDS" is from 50 MG/L to 2 G/L. A quick check finds seawater is 35 G/L. Oh oh! 17.5 times the max! Is the max really the max? Or is it a convient and/or tested figure because that's the most ever expected from city and/or well water? What happens if seawater were used? Would it clog/ruin the membrane? Would it remove 1/17 or 1/X as much TDS? What is the criteria for TDS? I'm not an expert on RO, but I believe that the higher the salt concentration the higher the osmotic pressure, and therefore the higher the pressure required to reverse the osmotic process. I've done some initial research, but need to do more. The above presented really to point out one has to research things all the way, as you've done. Not very difficult these days with the internet. How I remember spending hours, even days at libraries in the past. Isn't that the truth. I used to go down to the UT engineering library to research patents on microfilm. Now you can pull them up for free off the internet. Hmmm... Another research project. If one has say 25 GPH membranes, can one run less water through them, say from a 12V pump, and get 2 or 3 or 8 or whatever GPH? Say an engine driven or AC genset driven, if you have one, high volume pump and a 12V low volume? Less efficient? Would it even work? I honestly don't understand everything I know about RO! You have to have enough pressure to reverse the natural osmosis. Basically, its pre-filtering, pressure across the membrane, and flow on the "dirty" side of the membrane to keep the "debris" moving along so as not to clog the membrane. I notice there are two RO manufacturers within 30 minutes from here. They do the BIG stuff for the oil industry, 10,000 GPD. I think I might visit one or both. Okay Rick. Next project is to research and learn everything currently known about RO watermakers. Cruise ships have some monstrous systems, and I had the opportunity to view and discuss one with the chief engineer a few years back. The requirement for generating clean water on ships goes all the way back to the water used in steam boilers. The Navy was doing it back in WWII--probably before. Our Cornado's aft deck, under the mizzen boom, had a solar "patio roof". Took up the whole aft deck and hung a bit over the sides on the aft end. 5 X 7 feet as I recall. The new owner moved them to the lifelines. He added stainless tubing and fashioned mounts so they could swing down, vertically. Seems to work. This is probably what I'll have to do with at least a couple. The other two can go on an arch over the davits. I've seen boats outfitted like that. I always wonder what's going to happen to those panels when they catch a good boarding wave over the bow, but maybe they just plan on not doing that. Psych 101. "WE'LL get used to it." Gotcha ;-) Honestly, don't pretend you're 100% in heaven. In truth you'll have to get used to it too. Well, unless your idea of comfort is a 30-day canoe trip down the Amazon. :-) Well, I'm not 100% sure that I'll like living on the sailboat and cruising although I think I will. We're going to try it in small doses for a while and see how it goes. Thanks! Yep. Been there done that. Gonna do it again!!!! Hot dawg!!!! Well, _you_ must have liked it... Speaking of there. I'm in New Iberia, LA. Middle of the state about as close as you can get to the coast without living with the gators. I saw in another post you're Texas coast. What part? Just curious. We're in Austin, but the boat is in Palacios on the northern side of Matagorda Bay. Rick Don W. Learn how to take boat showers. Turn shower on, wet body, turn shower off, wash body, turn shower on and rinse off soap. Use maybe 2 gallons. Our 196 gallons will last about 2 weeks, not counting the bottle water we drink. We use sea water for washing dishes and depending where we are bathe in the sea and come aboard and rinse in fresh. krj |
#23
![]()
posted to rec.boats.cruising
|
|||
|
|||
![]() Learn how to take boat showers. Turn shower on, wet body, turn shower off, wash body, turn shower on and rinse off soap. Use maybe 2 gallons. Our 196 gallons will last about 2 weeks, not counting the bottle water we drink. We use sea water for washing dishes and depending where we are bathe in the sea and come aboard and rinse in fresh. krj I'm with you in theory, but in practice its just one more thing to not like about cruising. Its much easier to put in the _big_ RO watermaker, and not have to complain about how long the shower runs when she is doing her hair. Also, our 70 gallon tank would only last you 5 days at your rate of consumption, so on our boat you would either have to stay pretty close to a water tap, or have a good catchment system and only sail in rainy areas if you wanted to get by without a watermaker. YMMV, Don W. |
#24
![]()
posted to rec.boats.cruising
|
|||
|
|||
![]() "Don W" wrote I'm with you in theory, but in practice its just one more thing to not like about cruising. Its much easier to put in the _big_ RO watermaker, and not have to complain about how long the shower runs when she is doing her hair. Every girl wants a man like you. Easy to control! Also, our 70 gallon tank would only last you 5 days at your rate of consumption, so on our boat you would either have to stay pretty close to a water tap, or have a good catchment system and only sail in rainy areas if you wanted to get by without a watermaker. Don't forget to buy her a dishwasher, washer/drier, and an ice maker while you're at it. There's a good little boy! Freaking wimp! There's plenty of hot water at home in the shower. A boat's a boat - not a floating condo. And if it isn't a sailboat then it's worthless to begin with. Cheers, Ellen |
#25
![]()
posted to rec.boats.cruising
|
|||
|
|||
![]()
Ellen MacArthur wrote:
"Don W" wrote I'm with you in theory, but in practice its just one more thing to not like about cruising. Its much easier to put in the _big_ RO watermaker, and not have to complain about how long the shower runs when she is doing her hair. Every girl wants a man like you. Easy to control! Also, our 70 gallon tank would only last you 5 days at your rate of consumption, so on our boat you would either have to stay pretty close to a water tap, or have a good catchment system and only sail in rainy areas if you wanted to get by without a watermaker. Don't forget to buy her a dishwasher, washer/drier, and an ice maker while you're at it. There's a good little boy! Freaking wimp! There's plenty of hot water at home in the shower. A boat's a boat - not a floating condo. And if it isn't a sailboat then it's worthless to begin with. Cheers, Ellen **** you Ellen. How long have _you_ been married? For me its been nearly 1/4 century so far and I like her and she likes me. I'm not going to tie her to the mast and flog her if she complains. Cheerfully, Don W. |
#26
![]()
posted to rec.boats.cruising
|
|||
|
|||
![]()
Charlie Morgan wrote:
Don't forget to buy her a dishwasher, washer/drier, and an ice maker while you're at it. There's a good little boy! Freaking wimp! There's plenty of hot water at home in the shower. A boat's a boat - not a floating condo. And if it isn't a sailboat then it's worthless to begin with. Cheers, Ellen **** you Ellen. How long have _you_ been married? For me its been nearly 1/4 century so far and I like her and she likes me. I'm not going to tie her to the mast and flog her if she complains. Cheerfully, Don W. Before you get too excited, here's Ellen's website and photo: http://www.homestead.com/captneal/Captain.html CWM LOL. Charlie, If someone really annoys me, I just killfile them and move on. That banter was just a little "newsgroup sex" ![]() Don W. |
#27
![]()
posted to rec.boats.cruising
|
|||
|
|||
![]()
I'm glad that mystery is solved.
-- Roger Long |
#28
![]()
posted to rec.boats.cruising
|
|||
|
|||
![]()
On Fri, 16 Feb 2007 17:06:52 GMT, Don W
wrote: We used 4 to 6 gallons a day. High compared to many. One of the most wasteful water things is running the hot water tap, waiting for the hot to get there. Some folks put a valve in the line and route it back to the tank until it gets hot, close the valve and turn on the hot water tap. Well, you didn't have a watermaker either, so you were trying to conserve a lot. I measured what we used at home for showers one time, and was really surprised. Something like 20+ gallons each even with the low flow shower head. I could easily see us using 30-50 GPD with the two of us, and more with guests. No. Well actually yes we did have a watermaker. Of course we could have run it 24/7 and made 40 GPD, but the whole idea is it "costs" energy to run. Over about 8 to 10 GPD it would have overdrawn the solar "bank". Add in it was fairly noisy. "Navy" showers are the way to go. Wet, push the button on the shower head to turn it off. Soap, push the button and rinse. We used about a gallon. Okay, sometimes 2 gallons :-) You have to have enough pressure to reverse the natural osmosis. Basically, its pre-filtering, pressure across the membrane, and flow on the "dirty" side of the membrane to keep the "debris" moving along so as not to clog the membrane. Watermakers 101 (maybe we should change the subject line!): Not a real lot of system type info out there, but some neat equations and stuff. Yep, pressure is a function of molecular weight, dissociation and solute concentration, and in the case of salt the "osmotically effective" concentration of solute. All that to determine the osmotic pressure of seawater is approx 460 PSI and that it takes a higher pressure than that for it all to work. Note "higher", not a specific pressure. All the talk about reducing pressure for brackish water, etc., is not due to the process directly, but to the second requirment. To properly wash off stuff from the membrane. Some sources say 5% of the water should go through, others, specifically membrane manufacturers, say something else. One says a range of 10% to 20%. As an aside and real world observation, PUR said for the 40E it didn't matter - they said run in in the lake or canal (fresh), in the bay (brackish) or in the ocean (salt). And we did, with no damage or noticable increase or drop in product water output. Guess it was "made" to operate at the percentages encountered under all those conditions. Sooooo... One has to supply the proper volume of water per time unit at the proper pressure for a given size membrane/pressure vessel. Make that within a low to high range for both. That says a piston or plunger pump of X volume per stroke, operating at Y strokes per minute to supply that volume. So nice that water is incompressible :-) Force required to the piston/plunger = PSI required / area of piston/plunger. Strokes per minute = volume required / volume per stroke. Next is some way to regulate the brine flow out of the pressure vessel to maintain that pressure at that volume. Apparently the most used method is an orifice or needle valve. Adjust it to "bleed off" the brine at such a rate to maintain pressure from the properly sized pump. Another way I ran across is a pressure regulator. This on one that had an engine driven pump. The reason was that the pump output would vary with engine RPM. Even so the engine had to be run within certain RPM ranges. So now to my "ideal" 3 GPH, 12V watermaker. Research pumps. Maybe do some experimentation with a plain old pressure washer pump. Noticed Walmart has a cheap 1,600 PSI 3.8 GPM pressure washer. Little bitty thing. Must have a small motor. No, I'm not advocating turning it into a watermaker pump. Probably would turn to rust in weeks, if not days. Just shows high pressure water pumps are no big deal. Come to think of it, I've seen some really neat little plunger pumps around here. Back to the good old oil industry. 3 GPH output should take 20 GPH, .33 GPM at 15% product water. Subject to adjustment. Build a pump from scratch? Why not. I've got a metal lathe and other stuff in the shop. Have built stuff that operated at 10,000 PSI. Have built steam engines and very small, less than 1 CI, model diesel engines. Got a geared down wheelchair motor that'll run all day on 12V at 5 to 15 AMPS. Oops. Sorry to use this group for a napkin!!! Rick |
#29
![]()
posted to rec.boats.cruising
|
|||
|
|||
![]()
Rick Morel wrote:
Well, you didn't have a watermaker either, so you were trying to conserve a lot. I measured what we used at home for showers one time, and was really surprised. Something like 20+ gallons each even with the low flow shower head. I could easily see us using 30-50 GPD with the two of us, and more with guests. No. Well actually yes we did have a watermaker. Of course we could have run it 24/7 and made 40 GPD, but the whole idea is it "costs" energy to run. Over about 8 to 10 GPD it would have overdrawn the solar "bank". Add in it was fairly noisy. That noise is the worst problem in my estimation. I don't mind paying to run the genset or the watermaker, I just don't want to hear it or feel it. "Navy" showers are the way to go. Wet, push the button on the shower head to turn it off. Soap, push the button and rinse. We used about a gallon. Okay, sometimes 2 gallons :-) We'll give it a try. I can see how it works, but won't know if it will work for us until we're actually doing it. Right now, the marina we're in has nice hot showers available, so guess where we go to shower on mornings we sleep on the boat. You have to have enough pressure to reverse the natural osmosis. Basically, its pre-filtering, pressure across the membrane, and flow on the "dirty" side of the membrane to keep the "debris" moving along so as not to clog the membrane. Well, I was trying to be succinct. Watermakers 101 (maybe we should change the subject line!): Not a real lot of system type info out there, but some neat equations and stuff. Yep, pressure is a function of molecular weight, dissociation and solute concentration, and in the case of salt the "osmotically effective" concentration of solute. All that to determine the osmotic pressure of seawater is approx 460 PSI and that it takes a higher pressure than that for it all to work. Note "higher", not a specific pressure. Right. Although for a given effective size of membrane, you get more purified water out of it the higher the pressure is above the natural osmotic pressure. This works right up to the point where the membrane ruptures at which point you get a lot more water, but its not purified ;-) All the talk about reducing pressure for brackish water, etc., is not due to the process directly, but to the second requirment. To properly wash off stuff from the membrane. Some sources say 5% of the water should go through, others, specifically membrane manufacturers, say something else. One says a range of 10% to 20%. As an aside and real world observation, PUR said for the 40E it didn't matter - they said run in in the lake or canal (fresh), in the bay (brackish) or in the ocean (salt). And we did, with no damage or noticable increase or drop in product water output. Guess it was "made" to operate at the percentages encountered under all those conditions. Sooooo... One has to supply the proper volume of water per time unit at the proper pressure for a given size membrane/pressure vessel. Make that within a low to high range for both. That says a piston or plunger pump of X volume per stroke, operating at Y strokes per minute to supply that volume. So nice that water is incompressible :-) Force required to the piston/plunger = PSI required / area of piston/plunger. Strokes per minute = volume required / volume per stroke. Next is some way to regulate the brine flow out of the pressure vessel to maintain that pressure at that volume. Apparently the most used method is an orifice or needle valve. Adjust it to "bleed off" the brine at such a rate to maintain pressure from the properly sized pump. Another way I ran across is a pressure regulator. This on one that had an engine driven pump. The reason was that the pump output would vary with engine RPM. Even so the engine had to be run within certain RPM ranges. These are the basics. Obviously, the pressure regulator approach is better given a variable flow source. So now to my "ideal" 3 GPH, 12V watermaker. Research pumps. Maybe do some experimentation with a plain old pressure washer pump. Noticed Walmart has a cheap 1,600 PSI 3.8 GPM pressure washer. Little bitty thing. Must have a small motor. No, I'm not advocating turning it into a watermaker pump. Probably would turn to rust in weeks, if not days. Don't count on it. The pump in my pressure washer has a bronze housing, and 316 stainless balls and springs. Let's see. At 10% that would yield .38 GPM, or a little over 1 gal/3 minutes, so if mated with the appropriate membrane it would be a 20GPH system. Didn't you tell me not to get a 25GPH system?? ;-) Just shows high pressure water pumps are no big deal. Come to think of it, I've seen some really neat little plunger pumps around here. Back to the good old oil industry. 3 GPH output should take 20 GPH, .33 GPM at 15% product water. Subject to adjustment. 15% might be a little high, but not much. Maybe figure 10%. There you go again. We got the same number by different methods. Must be right ;-) Build a pump from scratch? Why not. I've got a metal lathe and other stuff in the shop. Have built stuff that operated at 10,000 PSI. Have built steam engines and very small, less than 1 CI, model diesel engines. Got a geared down wheelchair motor that'll run all day on 12V at 5 to 15 AMPS. Sounds like neat projects. My cousin Mark built a minature four cylinder steam or compressed air engine complete with cam and valve train in the engineering shop at WSU while I was there. The total displacement was about .2 CI. BTW, the high pressure pump on my airless sprayer is a kind of neat design. It basically has a spring loaded inlet valve, an spring loaded outlet valve, a liquid chamber, and a piston that intrudes into the liquid chamber. It is low flow rate, but puts out 2000PSI and will pump almost anything you want to run through it. You can adjust the pressure as well. The valves are ~$25 each, and the liquid chamber is milled aluminum. Really a pretty neat design all in all, and practically indestructible. Oops. Sorry to use this group for a napkin!!! Rick You can do it! But you will have to buy the membrane and filter housings. Remember that if you are going to pressurize the whole thing the pre-filter housings have to be stout as well. Of course, I don't know why you would do that... ;-) Don W. |
#30
![]()
posted to rec.boats.cruising
|
|||
|
|||
![]()
On Fri, 16 Feb 2007 23:46:47 -0600, Don W
wrote: You can do it! But you will have to buy the membrane and filter housings. Remember that if you are going to pressurize the whole thing the pre-filter housings have to be stout as well. Of course, I don't know why you would do that... ;-) Don W. Oddly the membrane seems to be the cheapest part. Well next to the pre-filters. Smallest membrane I found was a 6 GPH for $147. Pressure vessel for same was around $400. Okay, so 6 GPH is workable at 12V. Gonna' rest my brain... Then pick brain of an oilfield friend quite familiar with high pressure pumps and visit the two nearby oil field RO manufacturers. Rick |
Reply |
Thread Tools | Search this Thread |
Display Modes | |
|
|