How much water - usage aboard

The wind situation depends on the beer situation down here Fanie.

 

Thanks Jeff,

I would like to sustain 8 people for two weeks. The one wasting any water will do the dishes, scrub the deck, clean the fish, make food, serve drink to everyone aboard and do night watch. Geeezzz... it sounds like my wife already

2600 liters of water !! are you smuggeling the stuff ?

 

Masalai, for those prices of those watermakers I'll toe another boat just to carry water. Good grief.

 

Ahhhhh Fanie, Have you not realised that a boat is a hole in the water that requires continuous flow of money and resources to maintain that position...

Only fools try to emulate Moses and part the seas with their overpowered deep V monohulls.
They are not carrying the right stick and talking to the right power authorities- God not Money has been the only authority to "part the waters" for humanity to pass without getting wet....

Do a test at home, buy 3 plastic containers of 20 litres each and turn off the domestic water supply for a day then measure how much is used.... (Don't forget to count the coke and booze as people use alternative fluid supplies)

 

Moses who ?

I am collecting water (and other containers) currently... have 14 x 22L PE containers I can use for fuel or water... and expecting some more this week.

I doubt I would carry 2600 liters of water. You're supposed to float on it, not trying to board it. That's called shipwrecking or sinking.

 

First trip take 20 L container per person per week and tell them other goods account for 20kg each their clothes, food, booze / drugs, salt-soap (I doubled the luggage limit to cover booze needed to support fishing refreshments) - Next time adjust as needed

 

Phil,

Designing, building, and troubleshooting reverse osmosis desal systems of different sizes is a good part of how I have paid my bills for the past 20 years or so. Whether a reverse osmosis desal is worthwhile is an individual decision; I'd say "no" unless the voyage will be away from fresh water refills for more than 2 weeks. There have been significant advances in membrane technology over the past 10 years. Today's membranes yield the same quality water at 20-30% lower operating pressures, meaning 20-30% lower energy consumption, and devices that recover energy from the high pressure reject/concentrate water stream can reduce the power requirement another 10-15%. A well designed system can be used even in murky water; the key is multistage prefilters. Watermaker membrane elements aren't really "filters" in the usual sense. They operate at the molecular level, separating water molecules from salt/mineral molecules. To operate effectively, the membrane must see perfectly clear water. Color/murkiness is caused by microscopic particles, which are actually filtered out by the prefilters. Carrying a good number of prefilter elements is critical but easy, as they are low cost and very small and light. Understanding spare parts and how to make repairs is not difficult; apart from the membrane itself, everything else is simple mechanics and electrical.

Yes, even the smallest systems will cost 3-4 thousand. I don't think the extra power is as significant as you said; even the smallest systems can produce 40-50 liters of potable water in only a few hours. In general, though, as I said above, extra tankage, maybe a bit longer hull, is probably most effective unless you plan voyage legs of more than 2 weeks.

 

Wow!! Those Aussie retailers are doing well! You can get a fully automated 26 l/hr system retail here for under $6,500.; less for a "bare bones" system without automatic controls, less again for a smaller system.

Buuuuut, when all is said and done, it's a few thousand USD or AUD, and could be 30,000 - 50,000 ZAR for Fanie and Manie. I'd go with tanks if the voyage is limited to 2 weeks. 1000 liters should be enough for 8 people with some reserve, provided the captain communicates well and maintains discipline. Maybe show video of those acrobatic South African great whites and mention the overboard with a line option for water hoggers.

 

about 7.23 rand to the AU $ have a look here - this is the WHOLESALE interbank rate http://tradingroom.com.au/apps/mkt/forex.ac

 

I think the fresh water is lowballed in the first few posts. Maybe 2L a day if it was only for drinking and in survival conditions. For a working vessel it is more like 8L/person/day when cooking and hygene is factored in (even using MRE's it is closer to 4L/day than 2).

Normal allowances for stores are shown in this thread...

http://www.boatdesign.net/forums/showthread.php?t=14310