Reasonable water tank capacity for 43ft yacht?

[coopec]

Some time ago I made up X3 water tanks which (supposedly) fit down in the keel. Now that I am trying to fit them the front one is too high (even though I have used lead ballast instead of iron). If I just fit the aft two it will give me 84 Imp gallons. (As a comparison a 40ft Hallberg Rassy has a capacity of 114 Imp gallons) But as I plan to fit a watermaker is the front tank really necessary?

 

[starfire]

Depends on your usage, having been sailing with 3 teenage daughters, who could empty both tanks inside a day.

 

[ean_p]

Some time ago I made up X3 water tanks which (supposedly) fit down in the keel. Now that I am trying to fit them the front one is too high (even though I have used lead ballast instead of iron). If I just fit the aft two it will give me 84 Imp gallons. (As a comparison a 40ft Hallberg Rassy has a capacity of 114 Imp gallons) But as I plan to fit a watermaker is the front tank really necessary?


View attachment 164778

It strikes me that with a water maker then the more tankage the better ...... why make 40 gallons when you can make 140......!

 

[rogerthebodger]

Hi Clive as said depends on usage and do you have a water maker.

I have about 500 lit of storage plus a water maker so I can make fresh water when needed.

In my case I when for a high diesel storage tanks and a small diesel generator so I can create electrical power mains to charge battries and power my water maker so the only limit is the diesel capacity.

I do have solar panels so I really do not need to use my generator to charge batteries but I can id no sun

 

[dunedin]

How far are you travelling from civilisation?

What do you do WHEN the wstermaker and/or generator fails.
Not an IF, they will do sometime - and probably when a long way from a tap.

 

[Neeves]

If the water maker or gen set fails and you are a long way from succour - then whatever water you have left is drinking water. For everything else you use seawater - which worked for generations (including daughters or, in our case, granddaughter's ). In 25 years our water maker never failed (we did not have a gen set but we did have 2 engines).

We had 2 x 200l water tanks. They were interconnected but we could isolate each from the other.

When ever we ran one engine, or both, we ran the water maker - as the engines would usually produce more amps than we needed. Similarly we would also re-charge anything that needed charged, bake bread etc.

Because the water maker never failed we never had to restrict fresh water usage and 400l was fine. We would always have tank full and only use the other - but swap them about - so we never had 'old' water.

You could always supplement your stored water capacity by carrying 20l jerry cans or flexible plastic containers and fill them when you found you were running the engines/gen set and had 'extra' amps to make extra water. Store where convenient.

You only NEED fresh water to drink - 1l is sufficient for each person, though that will increase in warm climates. So - be generous 3l/person per day, that's 2 months for 2 people - now far will you be from freshwater?

Jonathan

 

[srm]

Only you can answer as it depends on how you intend to use the boat.

Your 84 gallons is around the capacity of my 35 ft boat. This has proved adequate for us, two people, mainly sailing in temperate waters and passages of up to three weeks without a water maker.

Incidentally, I found the easiest way to ration water use, even when sailing single handed, was to turn off the electric pump. That way only what was absolutely necessary was taken with the manual pumps.

 

[vyv_cox]

My water tank capacity is only 160 litres, plus 45 litres added for transom shower. We have cruised for half the year for the past 20 years and never ran out. But in the Med there are plenty of places to fill up when needed

 

[Neeves]

In anticipation of the need to ration water - you need 'some' seawater taps (and, obviously, a pump specifically for the seawater taps), specifically in the galley - but maybe also elsewhere. You could use a hand pump, for the seawater tap - but its the 21st Century - spend the money. Its a real pain to have to collect seawater in a bucket.

Jonathan

 

[B27]

Going long distances, you'll use the watermaker.
Worst case might be relatively local sailing, couple of guests on board, g swimming etc, so lots of showers each for a few days.

Long distance is probably less people, bottled water as a reserve for drinking, you don't need a huge amount to cross an ocean.

 

[NormanS]

Only you know what your rate of water consumption will be, and only you know the length of time that you will be between potential filling points. Many years ago, when we cruised in a Folkboat, all we had was five x two gallon containers. We obviously weren't doing ocean passages, but every time we went ashore we took any empty containers, and filled them. At that time the normal advice in the Clyde Cruising Club Sailing Directions was often, "water at burn".
Now, being slightly more civilized, much older, and with a fully fitted 36ft ketch, we have 100 gallons (450 litres), but we're still very careful with water. This is partly because we are almost never alongside. We have, on occasion, collected rain water. Obviously the sea water foot pump in the galley saves the use of a lot of fresh water.

 

[Kelpie]

3 people, 39ft boat, 370l main tank with about 100l reserve in containers. Usually lasts us about 5-6wks. We collect rainwater when possible, which goes in to its own dedicated containers and is only used for showering. Generally do washing up in salt water followed by fresh rinse.

 

[MontyMariner]

Depends on your usage, having been sailing with 3 teenage daughters, who could empty both tanks inside a day.

I can attest to that. 100 gal tank, with my two girls onboard I had to refill every other day. When I'm sailing solo it lasts for months.

 

[coopec]

I can attest to that. 100 gal tank, with my two girls onboard I had to refill every other day. When I'm sailing solo it lasts for months.

Ah! Someone just like me! I shower once a week (whether I need it or not)

 

[coopec]

"Never assume a marina's water is drinkable. And never use an unknown hose connected to a pier spigot regardless of how long you let it run before filling your tanks."
Water World - Worry Free Fresh Drinking Water - Marinalife

Certainly that is true out on the Pacific Islands. On Nauru Island we had water delivered in ship's holds and twice in my stay the water was rejected as not-potable.

 

[MontyMariner]

shower once a week

Shower! you must be joking, a bowl and a sponge in the cockpit . . . when necessary

 

[MontyMariner]

Never assume a marina's water is drinkable.

Not normally an issue in NW Europe, but I certainly agree about the hoses.

And never use an unknown hose connected to a pier spigot regardless of how long you let it run before filling your tanks

 

[coopec]

Hi Clive as said depends on usage and do you have a water maker.

I have about 500 lit of storage plus a water maker so I can make fresh water when needed.

In my case I when for a high diesel storage tanks and a small diesel generator so I can create electrical power mains to charge battries and power my water maker so the only limit is the diesel capacity.

I do have solar panels so I really do not need to use my generator to charge batteries but I can id no sun

Thanks Roger but to compare your yacht with mine is probably misleading! (I don't have a diesel auxiliary and my two 80W solar panels are shaded most of the day)

I am installing a Bosch 24V 55A alternator which apparently will output 76A if I spin it at a higher speed. Is that correct? I'd like to install something with a higher output but the cost out of reach at this stage. (I will replace the 80mm double V pulley with a 60mm pulley)

 

[NorthUp]

Thanks Roger but to compare your yacht with mine is probably misleading! (I don't have a diesel auxiliary and my two 80W solar panels are shaded most of the day)

I am installing a Bosch 24V 55A alternator which apparently will output 76A if I spin it at a higher speed. Is that correct? I'd like to install something with a higher output but the cost out of reach at this stage. (I will replace the 80mm double V pulley with a 60mm pulley)

You will need to rethink the vee belt drive, there is not much contact area with 60mm pulleys, and it's a tight radius for the belts. For nearly 2kW of power you'll need a cogged belt and pulleys, similar to ( wider) a car engine timing belt.
I would retain the existing alternator, and add a suitable pulley to the engine crankshaft to drive a second alternator.

 

[roaringgirl]

We crossed the Pacific last year with 4 adults and 2 kids on board for the longest voyage (which is the longest unavoidable journey in a circumnavigation) We have 3× 150L of tanks, 5× 20L jerry cans on deck and a 12V watermaker that produces 30L/h. We had as many showers as we wanted and filled our tanks most days. We had no problems whatsoever with the watermaker. The power to run it came from solar, wind and a Watt & Sea hydro-generator. We have 400Ah of LiFePO4 batteries and they were basically full the whole time we were underway.