Tankage for a month of splendid isolation.

[Gybe Ho]

My intention is not to become a tow-path hermit in my future narrowboat but as a design exercise I am trying estimate tank sizes. This design exercise is motivated by trying to reduce winter months in a marina which can add a £1500 chunk to the annual running costs for a continuous cruiser.

 

Here is my scenario for a month of "splendid isolation".

• 60ft narrowboat with one occupant.
• Modern vessel with better than average insulation.
• Pump-out toilet.
• 5kW stove and 5kW diesel heater with rads.
• The narrowboater pays off a 6 week Christmas marina bill and half way into January heads out with full water and diesel tanks and an empty blackwater tank. Assuming 30% of days dip below freezing at night what size tanks are needed for 30 days of total offgrid living on the towpath?

 

My estimate is:

• 5 liters per day fresh water for toilet flushing = 150 litre black water tank
• Two washing machine cycles per month = 100l
• 100 litres showering water per week.
• 10 litres per day drinking and kitchen.
• 150 + 100 + 100 + 400 + 300 = 1050l fresh water tank capacity.
• For heating I have read that mid winter some liveaboards consume 100l of diesel per month running their heating. I anticipate running a 50/50 diesel/solid-fuel mix = 50 litres + 10 bags of coal
• Given a 1000w array of solar I hope that solar will generate 1/3 kWh per day in February but that still leaves a deficit of 15 + ( 15 x 0.666 ) kWh in the month assuming 1 kWh per day electric consumption.
• Therefore I need to generate 25 kWh in the month and assuming 3 litres of diesel to generate 1kWh and push into an ample lithium bank = 75 litres of diesel for electricity. (Note: assume a Beta 43 with a couple of 100amp 24volt alternators)
• Total diesel for a static month on the tow path = 125 litres

 

This is not a pretty picture of a net-zero idyllic lifestyle but mid Jan to mid Feb is the most testing period for an off-grid continuous cruiser.

 

How far out are my estimates?
 

[Lady M]

What will you do if the canal and marina are frozen when it is time for you to depart?

[Alan de Enfield]

4 minutes ago, Gybe Ho said:

5 liters per day fresh water for toilet flushing = 150 litre black water tank

 

Why waste potable water on toilet flushing ?

Ours comes in from the canal / river (same as a yacht)

[dmr]

The canals don't freeze much, and not for long, and you are required to move every 14 days, so finding a water tap to fill up the water tank is not a big deal. Just keep a close eye on the weather forecast.

1000 litres water would be unusual on a narrowboat but can be done.

With a dump through pump out you get develop low flushing techniques so 5 litres per day is a huge over estimate (unless you eat a lot of bad food).

A big diesel tank would be good as diesel is not as easy to get as water.

[Mike Tee]

Forget the pump out toilet, get a cassette one. The canals do freeze, and Jan/Feb is classic freezing time and you can't carry the pump out tank to be emptied but you can carry a cassette or two - plus it's free!

[MtB]

I'd suggest finding space to store a month's-worth of food and booze will be as big a problem as any. 

 

 

[Gybe Ho]

16 minutes ago, Lady M said:

What will you do if the canal and marina are frozen when it is time for you to depart?

 

I would extend my marina stay as they cannot throw me out if the waterway is frozen. My theoretical departure date is just defined by an annual cruising budget. One extra marina week = 20 fewer summer season pints of beer in canalside pubs.

 

Frozen in on the towpath with a full black water tank is a real crisis.

[Tacet]

Allow about 50kg of solid fuel per week - and there should be little need to use the diesel heating.

 

A typical 200 litre diesel tank should last a month without too much risk.

 

Fresh water  - 1000 litres for one person for a month sounds a reasonably generous estimate.  Showering is probably the greatest consumer - depending on habits!

 

Don't know about pumpout.  But a Thetford cassette is maybe 5 days capacity per person, so it would be doable with sufficient spares.

 

I don't have the patience to stay in one place for any longer than circumstances demand.  But if I had your objective, I would be inclined to move once a fortnight to refill the fresh water tank and empty the cassettes. That is easily achievable.  It doesn't allow for being iced-in or trapped in a stoppage for ever - but nothing covers that entirely.

 

[Gybe Ho]

23 minutes ago, Alan de Enfield said:

Why waste potable water on toilet flushing ?

Ours comes in from the canal / river (same as a yacht)

 

Ok I had dismissed that option out of concern some canal detritus in a bucket of canal water would wreck the macerator. Here to learn.

[Alan de Enfield]

5 minutes ago, Gybe Ho said:

 

Ok I had dismissed that option out of concern some canal detritus in a bucket of canal water would wreck the macerator. Here to learn.

 

That is always a possibilty but a relatively coarse filter would overcome that.

But - why complicate things (liable to breakage and use electricity) by having a macerator ?

[nicknorman]

34 minutes ago, Gybe Ho said:

 

My estimate is:

• 5 liters per day fresh water for toilet flushing = 150 litre black water tank

 

5 litres of fresh water a day for 30 days into a 150litre tank doesn’t leave much room for the “human throughput”! I suggest you will need a big stick to poke it all down with!

 

We have a pump out toilet but it is of the dump-through type. I am not entirely sure what advantage a macerator toilet gives, unless the toilet has to be remote from the tank. It uses precious power and when it gets blocked or breaks it is not a nice job(bie). If necessary a dump through can be flushed with a bucket of canal water without any worries about damaging the toilet.

[Ewan123]

If we're careful, our 580l water tank lasts two of us 14 days (no washing machine, cassette toilet flushed by an efficient water pistol, usually just a standing wash at the basin - only a few showers). Your mileage will vary - some manage on much less than us, some could only do a week with the same.

 

We have enough cassettes to last a week, maybe two at a pinch if we're not on the boat 24/7. We can take them to empty if we get stuck behind a stoppage/frozen/broken down etc.

 

120l diesel tank lasts... I don't know, been years since it got near empty. Always got 40l spare in jerry cans and easy enough to fill from fuel boats or passing marinas.

 

We use heat logs for the fire, usually one pack per day, keep just over two weeks worth on board, delivery from Wickes or I pick it up if I've got a car for work.

 

For most things, I'd say just keep moving every week or two (passing facilities and marinas)  and you'll be alright.

[Gybe Ho]

3 hours ago, Tacet said:

Allow about 50kg of solid fuel per week - and there should be little need to use the diesel heating.

 

 

Much appreciate your figures and experience. I was expecting to let the fire burn out overnight and bring the accommodation up to temp each morning with the diesel central heating but this is based on theory.

 

Yes a 1000 litre watertank is bordering on the humongous, my prop might cavitate until a 1/4 ton of water is consumed. As you say moving on every 2 weeks reduces the water tankage requirement. I will have to dig out my old winter sailing clothing, I might enjoy a 2 hour January cruise with the right gear, insulated salopette trousers are a game changer.

 

My 100 litre per week showering water budget was a big guess. When sailing we used a 20 litre solar heated shower bag which equated to a very brief shower.

 

If I can afford an 800 Ah lithium bank I would leave the marina at the start of the month with a 5kWh credit which trims 15 litres off the the towpath generation budget. I hope that high tilt solar panels would perform better than my original budget above, so more savings there.

Edited July 14 by Gybe Ho

[blackrose]

27 minutes ago, Gybe Ho said:

Frozen in on the towpath with a full black water tank is a real crisis.

 

Well that's going to happen if you're continuously cruising all winter every winter.

 

Just fit a good cassette toilet and get a couple of spare cassettes and you've eliminated that potential problem.

[Jen-in-Wellies]

32 minutes ago, Tacet said:

Fresh water  - 1000 litres for one person for a month sounds a reasonably generous estimate.  Showering is probably the greatest consumer - depending on habits!

Forgo showering and the OP will have "splendid isolation" regardless of if he wants it, or not!

[GUMPY]

Having actually been frozen in at lock 14 on the Aylesbury Arm from Boxing day until the 1st Feb with a 900L water tank I can tell you it's not enough.

After the first few days I bought a 25L  container and filled it every day at work. Porta Potti was emptied at a sanitary station between work and the boat. Solid fuel I collected from my mooring stash. Lighting was by Aladdin paraffin lamps and I spent most nights in the pub to save electric.

Thickest the ice got was over 8 inches, on a positive note  canals don't freeze like that anymore.

 

ETA

Don't let the fire go out at all, it takes ages to get the boat back up to temperature and will generate condensation on all the cold surfaces.

Edited July 14 by GUMPY

[dmr]

29 minutes ago, blackrose said:

 

Well that's going to happen if you're continuously cruising all winter every winter.

 

Just fit a good cassette toilet and get a couple of spare cassettes and you've eliminated that potential problem.

 

In 14 years of CC'ing this has happened just once. A part self pumpout into a 25 litre platic container rescued us, so just once in 14 years have we been reduced to the indignity that cassette owners face every week 😀.

We did keep an emergency  portapotti under the bed for many years but it never got used so we gave it away.

Maybe the OP should also consider a compost loo even though this forum is not fond of them.

[roland elsdon]

I think we were moored at the general idiot that year. Water was dispensed into our cans from behind the bar, to supplement the main tank, showers at the university sports centre.

No it doesnt freeze like that any more, I remember endless problems getting the lister started , hand starting an engine on 30 grade oil covered in frost was a big problem, as we only heated the butty cabin.

[system 4-50]

I would allow an  estimate of 10% of the black water tank can't be got out  & 10% space needs to left at the top.  You do NOT want the sewage standing in the inflow pipe.

If the winter was bad I would get it pumped out when half full when possible, leaving 30 days capacity from that point.

Mascerators are great.  Drop throughs are primitive.  Depends on your perception of quality of life.  For me mascerator every time, with a nice china toilet.

The amount of water my mascerator used was adjustable on each visit.  

Its visitors that block mascerators.  You won't.  I took mine apart several times and it wasn't a dirty or smelly job.  

Remember that female visitors if you aim to have any tend to be more picky about toilet facilities than (more practical) men.

Winters are getting much milder so stock a little sunscreen cream.

Some on here recommend the banging 2 stones together method of laundry washing - I could not manage on just 2 loads per month and a decent washing machine is a must-have.

I have used laundrettes when necessary, an awful faff but effective.

Can't comment on the rest.

[GUMPY]

42 minutes ago, system 4-50 said:

I have used laundrettes when necessary, an awful faff but effective

Service washes at the launderette have always been the best way.

[cheesegas]

2 hours ago, Gybe Ho said:

For heating I have read that mid winter some liveaboards consume 100l of diesel per month running their heating. I anticipate running a 50/50 diesel/solid-fuel mix = 50 litres + 10 bags of coal

 

Given a 1000w array of solar I hope that solar will generate 1/3 kWh per day in February but that still leaves a deficit of 15 + ( 15 x 0.666 ) kWh in the month assuming 1 kWh per day electric consumption.

Your electricity figures are pretty accurate - I have a 1kw solar array with lithium batteries and run the fridge year round, 0.3kwh yield is probably the lowest I've got per day, usually 0.3-0.5 per day. 1kwh per day usage is about right for a liveaboard not particularly skimping on power usage, charging laptop/phone etc. 

 

In Jan/Feb, I use 2 bags of coal a week to keep the stove running 24/7, but if I'm away for more than a day I'll use the diesel heater to get the boat up to temperature before I get back, and sometimes for a little boost of heat at the back of the boat. It uses the main diesel tank so I don't know how much it uses in total, but I'd estimate it at 20 litres per month.

 

25 minutes ago, GUMPY said:

Service washes at the launderette have always been the best way.

I've found launderettes to be really hit and miss. Some have their machines set up for a short wash for your money, meaning you get clothes still smelling of detergent. Others are better though. I've been in one with a very grumpy lady who wouldn't give me change, some are very nice... Did the launderette thing for the first year of living aboard, fitting a washing machine was the best thing ever! No wasting half a day cycling to a launderette with a massive bag of washing, waiting an hour etc.

Edited July 14 by cheesegas
make it clearer

[LadyG]

5 hours ago, MtB said:

I'd suggest finding space to store a month's-worth of food and booze will be as big a problem as any. 

 

 

Deliveries are available from several sources, i used to get my stuff once a week, i have a Tesco crate which i can tie to my trolley, so not a problem if not adjacent to a road, but there will be road access to the services, so not difficult to co ordinate.

I think i ran the engine for a minimum of an hour a day to top up the batteries. 

My fuel tank is rarely below half full, so ive got 75l in hand. I think i estimated using 8-10l per week when not moving much.

I buy a 25kg sack of unwashed potatoes which provide baked potatoes for a month. Really its not a big deal.

 

4 hours ago, system 4-50 said:

 

I have used laundrettes when necessary, an awful faff but effective.

Can't comment on the rest.

Ring them up and arrange a service wash with delivery, i usually pay £20, (includes three sets of linen) every 3  weeks. Washing socks and suchlike by hand is fine in winter, but i dont want to try to dry sheets indoors.

Buy some clothes suitable for boating at charity shops: just got a super pair of  fashionable M&S jeans, with a brand new cardigan, £7.00 for both!

Dropped off four pairs of very unfashionable jeans.

 

Edited July 14 by LadyG

[Gybe Ho]

2 hours ago, MtB said:

I'd suggest finding space to store a month's-worth of food and booze will be as big a problem as any. 

 

 

Are you saying I won't find goats milk dispensaries at every mile marker along the cut?

Edited July 14 by Gybe Ho

[PeterF]

We have 420 litres fresh water, 2 on board, shower alternative days and the tank does 10 days. There is probably on average 1 washing machine load each week. Showers are of the navy type to conserve water.

 

Black water tank is 330 litres, recent Jabsco macerator toilet and if we pushed it to the limit could just make 3 weeks but it would be busting at the seams. We do try to minimise flush water and especially avoid using the double flush option unless circumstances make us.

 

Fuel is not something I can help with, we have a Refleks diesel stove so use a lot more for heating.

 

 

Edited July 14 by PeterF

[Gybe Ho]

1 hour ago, GUMPY said:

Having actually been frozen in at lock 14 on the Aylesbury Arm from Boxing day until the 1st Feb with a 900L water tank I can tell you it's not enough.

 

 

1963, 1947?