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03-13-2007, 07:37 PM
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#1
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Admiral
Join Date: Feb 2006
Home Port: Who cares really...
Vessel Name: T
Posts: 1,215
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My next big project will be the selection and installation of a water maker. My performance specifications for the water maker are the following:
Provide 50 – 100 gallons as quickly as possible
Quiet & compact (maybe even distributed) (2’x2’x3’)
Easy and low cost to maintain
Reliable (with warranty)
I’m looking for advice on drive type AC vs. DC vs. Engine drive. Also interested in knowing common failure modes.
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Top of my list at this time is the Village Marine modular NF600 which produces 25gph using 110AC. The kicker is, they offer life time warranty on the titanium high pressure pump.
Cost $5115
http://www.villagemarine.com/images/pdf_fi...frills.spec.pdf
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03-14-2007, 07:53 AM
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#2
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Commander
Join Date: Jan 2006
Posts: 159
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I used a PUR 35 (now katadyne) but the electrical useage and output was terrible. So was the noise. Now using a schenker which produces 8 gallons an hour at about 1 amp per gallon, same specifications as a spectra water maker but $3,000 USD less dear. If you plan to use your engine to run the watermaker then get an engine run watermaker. They are far cheaper and have the ability to make large amounts of water, depending on the number of membranes. Each membrane can produce about 8 gallons per hour, 30 liters, depending on the water temperature. Running the watermaker off the engine may also help put a biger load on the motor when just charging the batteries and cooler, a good thing for diesels. I don' trecommend AC models as they are far too inefficient. JMO
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A`ohe `ulu e loa`a i ka pokole o ka lou.
No breadfruit can be reached when the picking stick is too short.
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03-14-2007, 10:24 AM
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#3
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Ensign
Join Date: Oct 2006
Posts: 33
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Check out my post of 23rd Feb 'Water Makers/Generators.
Had some useful replies on how to make them which may help you choose one. Good hunting.
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03-14-2007, 01:37 PM
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#4
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Rear Admiral
Join Date: Sep 2005
Posts: 349
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We have a Katadyn / Pure 80 DC device and it works for us as compact and quiet, although only 12 litres per hour.
As we tend to run engine for 3 hours per day to charge energy when sailing - it gives ample for our two person daily need.
But agree with previous response - if you can fit engine driven watermaker you'll get more production plus load engine when charging electricity........
Cheers
JOHN
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03-14-2007, 07:04 PM
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#5
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Admiral
Join Date: Feb 2006
Home Port: Who cares really...
Vessel Name: T
Posts: 1,215
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Any recommendations on manufacturers of engine driven water makers...this is the one area that I haven't investigated.
Also, what is the basis for thinking the AC system is less efficient?
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03-15-2007, 04:58 AM
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#6
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Rear Admiral
Join Date: Feb 2007
Posts: 323
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Quote:
Originally Posted by Trim50
Also, what is the basis for thinking the AC system is less efficient?
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It's physics. The answers are underlined. The rest explains part of why it is that way.
Because energy conversation from one source to another is inefficient. Each time energy is converted in form; there is a power loss.
Likely you have a D.C. Generator driven by an internal combustion engine, but you need to power an A.C. motor. In the system that energy is likely stored or passes through a D.C. battery bank, (electrical to chemical back to electrical). In the system there could be an inverter, a converter, a stabilizer, a rectifier, a capacitor and a transformer, because electricity needs to be correct or “in tolerance”, when it is supplied to certain appliances, especially inductive loads (motors).
Power (energy) is a BIG problem! In obtaining, storing, releasing, harnessing, transferring and converting it.
The power loss is due to friction, and resistance, resulting in a voltage drop, with a by product of un-harnessed (wasted) heat. The heat is in the engine room (above ambient air), dissipated by the cooling system, some of which is expelled through the exhaust system. It took an energy source to may it hot, and it takes more energy to keep it cool.
Anything directly driven is more energy efficient. In this topic likely belt driven, though drive shaft would be better. Directly mounted to the crank shaft would be most efficient, but impractical, unless it had one end of the crank shaft available to couple to.
Look at the name plate of any A.C. electric motor. Look for the P.F. or Power Factor rating. You will not find one that says 100%. We have not solved that problem in engineering, yet. One that is rated in the mid 90's % (high efficiency rated) usually will cost more to buy, (because it cost more to design and manufacture) and will require less energy to operate.
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When in doubt, do the right thing.
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03-15-2007, 05:13 PM
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#7
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Admiral
Join Date: Feb 2006
Home Port: Who cares really...
Vessel Name: T
Posts: 1,215
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Aqua Man,
Nice write-up, however you are making one major incorrect assumption.
I have an AC generator
My plan is to charge batteries while making water for around 1.5 - 2.0 hours per/day. The primary reason that I don't like the idea of DC for water making is the cost and life of a large DC motor. I figure I can buy an AC motor anywhere in the world for a fraction of the cost of a DC motor and they typically last far longer than a brushed DC. Efficiencies of a good permanent magnet sychronous AC motor are approximately that of a DC motor and you don't have to be concerned about power factors.
I still plan to install solar for daily trickle charging so that I can keep my DC refrigeration cold while away from the boat for multiple days. Strangly enough, even my 12 Volt DC refrigeration runs off an inverted 24Volt 3-phase AC compressor for the very same reason. Even with the inverter, the 3-phase AC compressor is more efficient and reliable than any DC motor driven system.
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03-15-2007, 06:28 PM
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#8
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Rear Admiral
Join Date: Feb 2007
Posts: 323
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Trim50,
I have a career (**) in working with this stuff, "electro-mechanical-hydraulic" systems, building (manufacturing and fabricating components), trouble shooting, and repairing equipment and systems. I love the challenge! Re-reading my write up, I could have and maybe should have written it differently.
I was describing systems in general, attempting to answer the question of why an electrical driven system may be less efficient that a mechanical driven system.
When I wrote, "Likely you have a D.C. generator", I was thinking of belt driven D.C. generator running off the side of your main engine, to charge the battery bank. I wasn't even thinking of a stand alone electrical power generator or alternator.
It comes down to what systems you have, what you want to accomplish, how you want to put it all together, considering the purchase price, and future operating costs.
~ ~ ~
** Career: If anybody is paying close attention to what I say I have done, somebody is going to wonder, "Hey! How could this guy have done all those things in life time and only be a few days shy of 51?"
I was twice a citizen. I had parallel careers.
* Military Twenty six years as an Army National Guard (Reserve) Officer (Combat Engineer), with 3 years enlisted time, and 3 years of combined Active Duty Tours.
* I also went to college, worked at continuing education and self-improvement, had a civilian career, and side line self-employment. Almost always I had two or three, jobs or schools, simultaneously. In life sometimes I missed sleep or other things, like TV shows, but Oh Well.... I didn't miss much....
~ ~ ~
Best wishes with the water maker project!
EDITED TO ADD:
Swagman said it (Above):
"We have a Katadyn / Pure 80 DC device and it works for us as compact and quiet, although only 12 litres per hour."
Whatever works for you.
__________________
When in doubt, do the right thing.
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03-15-2007, 06:45 PM
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#9
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Retired Mod
Join Date: Mar 2007
Home Port: Durban
Posts: 2,984
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Quote:
My next big project will be the selection and installation of a water maker.
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You're going to hate me for this.
I don't believe that you can rely 100% on a water-maker (they are notorious) for long passages. So, you must load backup supplies. If you load this "extra" weight anyway, why not just load enough bottled water for drinking for the duration of the passage (+ 30%) and use the boat's tankage for washing, etc. If the water-maker is producing as expected then you can shower in fresh water more often (always keeping an eye on the tank levels) and don't forget the possibility of (hopefully) catching some rainwater while underway.
The feedback that I have had on water-makers from cruisers "out there" is that they are a HEADACHE! Very expensive to install and a pain to maintain and service.
Are they worth it?
I told you that you'd hate me.
: Most sections
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03-15-2007, 07:34 PM
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#10
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Rear Admiral
Join Date: Feb 2007
Posts: 323
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Lighthouse,
I don't hate you at all, in anyway, fashion or form. I very much appreciate you, you comments, and your board.
I know very little about yacht water makers. (Cruiser wanne be in study)
I know something about water and making it. (Combat Engineer / US ARMY Corps of Engineers) - Early in my career that was our responsibility. Later that was re-thought and reassigned to the Quarter Masters.
Your comments are most valid, but my plan is to include both.
* Take enough potable water with for the passage, with a more than adequate, emergency reserve for survival only (drinking).
* AND have a water maker system on board, for comfort, (at a greater cost) and to continually restock the water storage reserves.
If systems fail in making water, than the water usage plan changes as appropriate (conservation) and maybe drastically to rationing and survival mode.
By all means catch rain water. It's fresh, FREE, and acceptable. The reliability varies.
__________________
When in doubt, do the right thing.
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03-15-2007, 10:02 PM
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#11
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Admiral
Join Date: Feb 2006
Home Port: Who cares really...
Vessel Name: T
Posts: 1,215
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Lighthouse,
Well, I certainly have enough water tankage to achieve long passages without a watermaker 500gal. However, I really want that feeling of being completely disconnected from the grid when I leave. A good friend of mine from the dock that has 10's of thousands of cruising miles under his hull suggested that I convert some of my water tankage to fuel...and I'm still contemplating that one. He is the one that recommended the more expensive Village Marine water maker as well. He just finished a 3 year trip with his and it never had an issue.
What do you think of the tankage conversion idea?
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03-15-2007, 10:38 PM
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#12
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Retired Mod
Join Date: Mar 2007
Home Port: Durban
Posts: 2,984
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Quote:
Originally Posted by Trim50
Lighthouse,
What do you think of the tankage conversion idea?
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This is a loooong story but I'll make it as short as possible.
Our tankages on our 44' steel ketch was:
* Water = 1,200L
* Fuel = 1,000L for 80hp Lehman
Crossing the Indian Ocean - making good time, looking like 24/25 days.
Roughly half-way - becalmed!
Full fuel tank - startup the motor.
After 5 mins - no water pumping through. Shut down.
Open the raw-water pump - impeller shredded (New, 6 hours of motoring).
Get out the spare.
DISASTER!! Right packing box - wrong impeller!! (from the store - lesson learned here). Only one spare - afterall, we are a sailing yacht!
In case of emergency, pulled out spare hose and rigged raw water from the genset outlet to main engine inlet - cannot run main engine for long with this "hot" water intake.
We were becalmed for TEN days - not a breath to even take the "glass" off the sea. It was stifling hot. Long story but the passage eventually took 40 days.
So, what would you rather have had? Extra fuel? Extra water?
: Most sections
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03-15-2007, 11:24 PM
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#13
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Admiral
Join Date: Feb 2006
Home Port: Who cares really...
Vessel Name: T
Posts: 1,215
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Good, that was pretty much my feeling!
He's a really smart guy, but he is after-all a power boater with 2 gensets, 2 engines, 2 water makers, 2 autopilots....everything but two wives.
FYI...I have the same engine and will make sure I have several copies of the right raw water pump!
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03-16-2007, 12:57 AM
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#14
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Admiral
Join Date: Jan 2005
Home Port: Darwin
Vessel Name: Sandettie
Posts: 1,917
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I am not a luddite, but I have been opposing specific areas for modification on my boat for years. Occasionally, I seriously consider updates, but whether for economic or other practical reasons I always seem to settle on what is already in place and working.
I have 450 litres in total of fridge/freezer space in two separate cabinets. These are run by an engine driven eutectic system which has never given me any trouble.(And I still have almost 18kg of R12) I have bought a danfoss 50 ltr, 12v portable for times when I am away from the boat and when in between trips.
The other area of change I avoid is watermaking. Many times I have been close to making the decision to buy a system. However almost like magic, every time I come close to picking up the phone to place an order, I read a tale of such inconvenience about watermakers, that I shy away from them yet again.
My current position is that I have recently added another underfloor tank of 300ltrs to give me just over 1000ltrs. I am going to add a Seagull Mk IV water filter to a dedicated drinking water supply line to the galley to overcome any contamination problems. The stainless steel filter is airline quality and is about 15% of the cost of a mid-range water maker.
Central to this decision and apart from the huge cost of a watermaker, is my solar charging capability. I run my engine for about 25 minutes each day but rarely use the diesel for propulsion; I have no desire to install a washing machine, and with 4 separate water tanks, each individually plumbed, I feel that 1000ltrs is sufficient to keep me out of trouble.
BUT, I will not tell my beautiful girl that Trim is installing a watermaker and has 2300 ltrs of water tankage. That's a lot of water! (I wonder how empty tanks would affect the boat's trim as that weight of water would equal about 10% of the weight of a standard 50' yacht).
Anyway, that's my water story and the upshot is that maintenance is minimal, save for an annual emptying to clean the tanks and check the non return valves....Butcha have ta do that, watermaker or not.
Cheers.
David
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" if at first you don't succeed....Redefine success"!
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03-16-2007, 04:06 AM
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#15
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Admiral
Join Date: Jul 2004
Posts: 2,098
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sv Watermelon had 44 gallons of fuel (about 170 liters), and 75 gallons of water (~285 liters).
We had a watermaker that we rarely used because it only made 4 liters per hour, and we couldn't run the engine long enough to make enough water to be worth the effort.
Our longest passage was 19 days, 3 people aboard. One heavy rainstorm helped to replenish our water supply, though probably no more than 10 gallons was collected - too rough to do better. We did not run out of water or fuel.
Only once were we down to our last 2 liters of water with no idea how we were going to get more, in Misima, Papua New Guinea. We had stayed in an uninhabited and dry archipelago too long, figuring we would get water when we got to Misima, only to learn that the local water was not potable. With our usual luck, we met an island freighter captain in port who happily gave us as much water as we could accept. People are just so nice everywhere.
I had a salt water foot pump to wash dishes, then rinse the salt off with fresh water. We didn't wear a lot of clothes in the tropics, bathed with salt water with a fresh water rinse.
A gallon of water weighs about 8.3 pounds (1 liter = 1 kilogram), so 500 gallons of water is not only a whole lot of water, it weighs a whole lot. I can imagine how the boat would sail quite differently with full compared to nearly empty tanks.
However, I have to remind myself that everybody approaches cruising, and managing their resources, differently. I didn't feel deprived by what we carried (or didn't carry) on Watermelon. I'm still very careful about our water consumption even though we no longer cross oceans or are far from a source of water. For others, our existence would be considered intolerable.
Having a watermaker is a lot easier than the lugging of jerry jugs to the boat, until it breaks. But you might miss out on some very interesting people met at the local water source, and some very amusing stories about getting, storing, sharing, collecting water. then again, just about everything you experience while cruising provides some very amusing stories.
Oh! the story of the wrong impeller.
Peter usually installs the new spare part and keeps the not-broken part as the spare. That way he knows that his spare part will work if it's needed. He would rotate our pumps - new one for fresh water, the old fresh water for one of the other less critical pumps, on down, with the now oldest, but still working, pump kept as the emergency spare. I would never have thought of doing that, but it makes sense, and stood us well all these years.
fair winds,
Jeanne
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03-16-2007, 07:17 AM
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#16
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Admiral
Join Date: Feb 2006
Home Port: Who cares really...
Vessel Name: T
Posts: 1,215
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Quote:
Originally Posted by Auzzee
BUT, I will not tell my beautiful girl that Trim is installing a watermaker and has 2300 ltrs of water tankage. That's a lot of water! (I wonder how empty tanks would affect the boat's trim as that weight of water would equal about 10% of the weight of a standard 50' yacht).
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Empty tanks have a dramatic affect on the way the boat sits in the water and how she handles wind. The boat was designed and built in the late 70s before water making with 2 - 250 gallon stainless tanks set far port & starboard at midship. Believe it or not, I also have another 50 gallon keel tank for extra water storage that I don't use and keep empty. Fuel tank is in the keel. I prefer how she sails with full tanks. When the tanks are empty, she rides about 3-4 inches higher in the water.
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03-26-2007, 10:48 AM
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#17
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Retired Mod
Join Date: Mar 2007
Home Port: Durban
Posts: 2,984
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An "alternative" watermaker (towed) HERE
Prices HERE
: Most sections
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03-26-2007, 02:25 PM
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#18
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Ensign
Join Date: Mar 2007
Posts: 6
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I sell Village, RWO and Spectra. My Spectra customers have been the most satisfied with their units. Personally, I've cruised twice without any watermaker. I asked myself how much water could I buy before I broke even on the purchase (much less the maintenance headaches and expense. Where you are going is critical to the decision. Is the ambient water in which you are anchored satisfactory for RO (eg. Trinidad), can I get to the dock or do I have to hoof and tote, how much does it rain for capture and what are my crossing leg limitations. In my island cruising I've never run out of water and my capacity was 75 gals in tanks and 15 on deck. I the eastern caribbean I was almost able to keep up with a simple collection system and only brought water for drinking aboard. My worst experience was having to walk 1/4 mile to the nearest spigot in Grenada. The rum served at the local store was so good and cold, that it never seemed to bother me.
If you are outfitting for a cruise, you can always add it later. Take an impromptu survey of other cruisers. Part of the KISS strategy.
Jeff
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03-26-2007, 04:39 PM
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#19
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Admiral
Join Date: Sep 2005
Posts: 1,619
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Quote:
Originally Posted by Trim50
Empty tanks have a dramatic affect on the way the boat sits in the water and how she handles wind.
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Trim 50 is right about the empty tanks but I think we may also be missing another important point.
A full and "pressed up" tank will increase the boats metecentric height (i.e. the centre of gravity will move towards the tank - and I assume the tank is low in the boat such as under the cabin sole) That's fine.
An empty tank will then decrease the boat's stabilty but should not effect it seriously although it will affact the boat's trim. What is worse is a slack tank which adversely affects the boat's stability.
As water is consumed from a tank, the tank becomes "slack" in seaman's terms. This means that the water in the tank (which should be baffled anyway) can move arround and will naturally end up on the lee side. Normally this would not be a problem in a yacht as there may only be one or two tanks. However, yachts carrying large quantities of water should be aware of the risk of slack tanks. This is beat demonstrated by holding a tray with a glass of water on it balanced on one hand. No problems! Take the glass away and pour the water onto the tray and try do balancing act again and the problem will become immediately apparant. (Wear bathing gear when doing this).
Now we are aware of the problem how do we avoid it? The answer is simple. Divide your water up in severeal tanks. No tank should be more than half the hull bredth (except a forepeak or afterpeak tank). Ensure the tanks are baffled and, most importantly, use water from one tank at a time and empty that tank before moving on to the next.
This may be a little off topic but in the interest of safety I thiought it should be included.
Aye
Stephen
Yacht NAUSIKAA
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03-26-2007, 10:36 PM
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#20
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Commander
Join Date: Jan 2006
Posts: 159
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A watermaker is a critical need for my cruising. Many South Pacific islands have no water available or water that will kill you if you drink it. Depends on the type of cruising you are doing. If you intend to spend a lot of time in major ports and population centers then a watermaker may not be useful---ON A MONOHULL. If you intend to be in remote islands, cruise off the typical paths, make long passages then a watermaker is very important. If you are on a catamaran then carrying 50 gallons of water at 400 lbs and a 25 lbs watermaker is far better then carrying 2500 lbs of water. It's also a good idea in a monohull.
I left Hawai'i for Tahiti, about 2600 miles. Easy sailing of 13 days total and could easily do without a watermaker. I stopped in Fanning Island for 2 weeks, fishing, swiming, snorkelling, etc. No water was available there. Without the watermaker I would have needed to proceed to Tahiti without stopping. I have 2 tanks and contaminated one by accident before arriving in Fanning. Without the watermaker I would have travelled to obtain a water supply. With the watermaker I travel for interesting destinations. Why let the water situation determine your next destination? I like fresh water showers and clean clothes but use water sparingly. Water never determines my cruising destination or schedule and I think carrying around 1 or 2 tons is not all that practical.
I will post more on the efficiency of water makers, dc, ac and motor driven systems, shortly.
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A`ohe `ulu e loa`a i ka pokole o ka lou.
No breadfruit can be reached when the picking stick is too short.
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