Fresh water tankage sizing for Atlantic crossing

[Bob666]

Hi!

Have a Norlin 37 with 2 x 90 l fresh water tanks original.

That makes 180 l, or for you Americans: 48 gallons.

I have counted many times. We are two adults, and three kids, going from Las Palmas to S:t Lucia (ARC). We'll be going back half a year later or so.

Might be only two kids on the crossing actually. I came up with 900 l or so, to be safe.

Not sure if one should employ the same caution practice as with cave diving, one third until you turn around, one third for the return trip, one third left as spare?

I don't think we'll be using up 900 litres. Anyway, I face two major choices:

1. Keep the boat as it is and add lots of 5 or 10 litre water canisters from the Supermercado in Las Palmas:
3d model water bottle 5 liter
+ some soft water tanks.

2. Rebuild the water tank system in the boat and/or add to it.
If so, should I go for additional tanks or plumb the stainless ones to additional tanks? Right now they are separated and have two separate intakes on deck.
Maybe some extra soft water tanks in this scenario as well. And of course some supermercado water canisters, albeit fewer than scenario one.

Cheers

[barnakiel]

Water is easier because you do need it. More is always better here.

Count bare minimum 1.5 liter per person per day. MINIMUM. I am extreme, and I guess I may smell a little bit every time we are done.

5x60x1.5, I come at 450 liters. More is better. Much more is much better.

A very fine alternative is get a watermaker, this gives you unlimited water and makes everyone onboard VERY happy. Especially any ladies or girls with long hair ...

Your dave caving example holds: use little at the start, dig into the overhead as you are covering the distance. You only need half of your overhead when you are half way thru.

PS Local spring water is very good. I can recommend Agua de Terror. It only sounds frightening, in fact it is prime quality.

b.
(from Las Palmas)

[Snowpetrel]

I like to have 3 litres per person per day, so how long is it? Something like 30 days? (2700nm at 0.8xsqr rt lwl or 4 knots is 27 days). Makes 450 litres. Prehaps kids would use less, but maybe not. Decent margin of safety is that you can safely cut down to 1.5 litres per person if needed. And survive on 1 litre per person per day at a pinch.

I have used bottled water stashed thoughout the boat as extra. Worked well, and good redundancy.

I am more concerned on boats with fewer big tanks. One lost tank and you are in trouble. A watermaker is good, but you still need a certain minimum in case it (or the charging system driving it) fails.

With 450 litres you would probably have enough for the odd bird bath. And hopefully a decent margin left at the end of the voyage. Use salt water to wash dishes. Tins rather than dried food. Uht milk is also liquid and counts towards your ration.

Many people have managed with much less water. A way to catch rain is good for bonus but probably shouldnt be relied upon.

[Snowpetrel]

I think any of your proposed solutions would work. Obvously just using extra jerry cans and bottles is the easiest and cheapest, but if you want more water for regular cruising and have a nice spot to put it, it might be worth adding another medium sized tank. Plumbed separately. The flexible tanks are an easy option. Really alot depends on the boat and how you use it. For a one off atlantic trip extra bottles and jerry cans are fine.

I hate jerry cans on deck, ideally you can fit them below somewhere. Or in the cockpit.

Sent from my SM-G930F using Cruisers Sailing Forum mobile app

[sy_gilana]

We work on 15L per person per day. Includes tea, coffee, cooking, washing and laundry.
On crossings we store 30L water in the dinghy.
Get an Eco-sistems watermaker from Barcelona.

[nauticalnomad]

Originally Posted by sy_gilana

We work on 15L per person per day. Includes tea, coffee, cooking, washing and laundry.
On crossings we store 30L water in the dinghy.
Get an Eco-sistems watermaker from Barcelona.

15 litres a day per person... And Washing and Laundry.. WTH..

[Snowpetrel]

Originally Posted by sy_gilana

We work on 15L per person per day. Includes tea, coffee, cooking, washing and laundry.

Luxury! I normally cook in 50:50 salt, do dishes in salt water and stink! But I havent gone thirsty yet..

[Bob666]

Hi!

Many interesting answers! Well I might as well have a separate tank, must it be stainless or is Polyethene ok? The soft ones, I am worried about them breaking. Stainless steel is stainless steel. Doesn't break easily.

A separated tank with its own valve, filled by pulling the hose down into the boat. For drinking purposes.

We won't buy a watermaker. If we ever do the round the world trip, we will (and get a 53 feet Bruce Roberts or similar...). Trying to keep costs down a bit this time.

I thought you would be using the bought water first, and only use the water tanks when you run out of bought water? Seen pictures of people having bought water bottles all over the saloon floor, having to climb over them. That's perfectly alright I suppose.

The way we do it (or should I say did it, with previous 30 feet boat, but the same goes for our Norlin 37 I suppose) here in the Baltic Archipelago (Eastern Swedish coast) when we are out say six weeks in a row in the summer, is that we top up in marinas once in a while. We always cook, unless in dirty marinas, in salt water. We do the dishes in salt water. We have hot water in the galley from the engine (this boat, not previous one, we boiled water for the dishes, or tried washing up with cold sea water, with limited success...).

We usually hang out in natural harbours (= no cost + nice) so water is pretty clean. And you don't have to add so much salt when boiling pasta also...

I cleaned myself after 3 days in a row of sailing last weekend by using a plastic bottle of 1,5 litres, filled it half with water from our hot water tank (15 l). The hot water tank is heated when running the engine and keeps hot for 8 hours or so. The other half I was cold sea water. Makes it reasonably warm.

Pour it over yourself, then add shampoo and soap for hair and body. You do this either in the cockpit or on the bridge, cliffs or whereever you are. Next, you pour another 1,5 l bottle of warm water over yourself. Short hair is a bonus.

Still some schampoo left, so I jumped into the 10 degrees sea water for a minute. You get goose bumps but it's nice afterwards. Make sure to have the diesel heater running inside the boat. Or if it's sunny, find a place with no wind. To get warm fast afterwards.

I don't find it that problematic, as some people seem to do, with using salt water all the time.

For the teeth, I rinse them using salt water the first 2-3 times after having a toothbrush. Tastes no good, but I am not swallowing it. Final time I take some fresh water and rinse the mouth.

That's how we do it over here. Might as well work when underway going south I suppose? And in marinas (will be quite a few going from Sweden -> Las Palmas) you have all the luxuries: showers, saunas etc.

We have a dinghy so we can buy water with it once we're over in the Carribbean I suppose.

As a side note, nobody ever buys water in Sweden. If you ever go here - it's quite expensive to buy bottled water, but you can drink the tap water everywhere so no need... In most European cities I've been you can drink the tap water. It's different in the Carribbean I suppose.

Cheers

[barnakiel]

Should you find yourself with limited water, you can use a plant sprayer to have a mini mini shower. Others will employ a sponge.

Getting stark naked and standing in the rain (if there is any) is good too, just bleeding cold. Still, this is what I recommend to all my opposite sex, young, crew.

One does not get very dirty on passages but off course the body is the body and it needs good attention as much as your navigation and your ship. Especially so when you share the limited space of the boat with others and considering the fact that ventilation at sea is restricted.

We wash the dishes in salt water. No issues. We use French arcopal bowls that are super easy to clean with sea water.

We never use salt water to shower or wash ourselves - my mate has extra long hair and it takes at least a gallon of water to get the salt out of her beautiful head. We do sometimes take a salty shower, but this is not a voluntary action.

If I could afford, I would go with a watermaker and tank ONLY the amount of water I consider our survival rate for the passage and the overhead. This would make for a lighter and faster ship which in turn reduces our water needs.

Cheers,
b.

[reed1v]

Presume you checked out adding a water maker? We did that for 10 years without a problem(assuming you keep to the cleaning schedule and keep it running most of the time.

[a64pilot]

Rule of thirds is a good rule for water, and fuel.
Of course since we aren't going half way and then returning, you arrive with 1/3 remaining, not 2/3.
I don't have a watermaker yet either, and don't do that long a passages, just four days or so, but my plan is that I lose my water tank soon after leaving. Lots of ways for your tank to empty itself, so I have enough water carried in 5 gl jugs and some store bought water to get us by, here you can buy it in 2.5 gl containers like milk jugs really cheap.
I've found that water is a luxury, not having to worry about conserving water really adds to quality of life, you can tolerate a whole lot more if you feel clean as opposed to feeling grungy.
It's hard to have too much water.

[Ardbeg]

Thought about a solar water maker?
Solar powered reverse osmosis sea water desalinators

[w1651]

In the southwest of the United States they recommend 1 gallon per person per day. I know the Atlantic probably isn't as dry or hot as the Southwest is but I always use this line of thinking for my own boat and travels. Just to be safe more is better. And top off regularly with rainwater or hose at the dock. Just my 2cents.

[Sea Dreaming]

I am of the more is better crowd. 1.5 liters a day is really a survival ration. Thats drinking water only. I am always shocked by how little water some people claim. You really want to do more than survive your passage. Long term dehydration leads to a kinds of health issues. Dont mess around. Plan for at least 1 gallon per person per day just for drinking water. Double that to be safe. If you lose any jerry cans in a storm, for example, you wont be thrown into survival mode.
I promise you, if survival is all you do plan for, you will always be a solo sailor.

[seasick]

I personally like to have five or six, five gallon plastic jerry cans of water on deck, tied to the life lines or in the cockpit. I always have a knife lashed to these cans in case the boat goes down in a hurry and I need to take to the life raft or skiff.

We usually dedicate one of these cans for rinsing off salt water after a seawater shower by pouring a quart from it into a tea pot. We refill this one jug with rain catchment.

I see you have posted a similar thread regarding diesel capacity. Consider that if you add a water maker your diesel consumption will increase.

Jerry cans come in handy in the Caribbean for ferrying out water to your boat.