Compact but comfy

[Bill2]

In this age of cut-backs, I thought I would try to find a specification for a comfortable “live-aboard” narrow boat with the lowest possible running cost.

 

The main, unavoidable, running costs are licence fee and moorings, both are length dependant so a short narrow boat is indicated. I chose 35 foot as an achievable length to keep the “comfortable” specification satisfied,(saving £290 pa on a 70 footer licence and up to £1400 pa on a marina berth.). Also allows a 35 foot rigidly attached butty in more affluent times!

Another overhead cost or comfort inconvenience is the toilet, cost of pump-out ( £5 per week? £250 pa ) or inconvenience of emptying. Avoided by use of an earth closet.

 

This saving of ca. £2000 pa will help justify the expensive feature:

 

Hybrid drive from www.hybridmarine.co.uk on the Isle of wight. The result of using their drive system is a massive price for the engine (doubled) and a massive amount of electrical power( equivalent to three thousand amp hours at 12 volts ).

 

The makers claim to halve fuel consumption ( saving the cost of a gallon of fuel for every day cruising ).

The copious supply of electric power allows us to make capital savings eg:

 

No 12 volt wiring needed,

No plumbing or boiler for central heating.

If we cook electric the ventilation requirement drops dramatically,

minimum effective area (mm2) = [2200xU]+[650xP]+[440xF] Where: U = total input rating (kW) for all appliances (including cookers) without flues F = input rating (kW) for all open or closed flue appliances P = number of people for which the compartment is designed

gas cooker 5kw=U=11000

stove 8kw=F=3520

people 2=P=1300

Normal boat needs 15820 sq.mm. of ventilation

This boat needs 1300 sq.mm.

Ten times less ventilation is about ten times less heat loss. I.e. 8kw stove replaced by 1kw electric heater!

 

I drew up a “Word” document which I sent to several builders, but I haven’t been able to get even a + or - £5000 estimate.

 

What next?

[Graham Davis]

How do you use an earth closet on a boat, or do you mean a composting toilet?

[Bill2]

How do you use an earth closet on a boat, or do you mean a composting toilet?

OK Composting toilet (it makes earth though)

[Paul C]

There's a reason why most boats use similar equipment. Personally, I'd forget about hybrid drive and draw up the specification more/less similar to other boats. For example, there's several flaws in your plan:

 

- Boat will still need the same amount of wiring (it will be 240V not 12V though).

- You'll still need plumbing for hot water.

- 10x less ventilation ISN'T 10x less heat loss, heat loss will occur in many places other than the vents. A lot of boaters seem to get by with a solid fuel stove and 'free' wood foraged from the environment, and with the small interior size of a narrowboat, no issues at all with heating the interior up to a comfortable level.

 

Don't forget that 35 foot boat length (half of a 70 footer) doesn't mean half the cabin space, it means less than half, because you can't reduce the open areas at bow/stern that much. 35' is pretty small for a liveaboard. There's a reason why liveaboard boats tend to be around 57 feet.

[Paul C]

EDIT: just realised, you're planning to not have 12V electrics at all - does this mean you'd rely on an engine generator to make the 240V? ie with no engine running, no power? You need power between 8pm and 8am surely??? Fridge? Evening lighting, telly, etc? So you'll need batteries --> 12V electrical system.

[Caprifool]

You don't "need" plumbing, hot or cold. I don't have any plumbing in my house!

[MikeV]

So you'll need batteries --> 12V electrical system.

Or a 24V or 48V system. Either way a big battery bank will be needed to run a 1KW heater + the other usual appliances when the engine is not running. A 1kW heater running for, say, 5 hours would consume 105 amp hours @48V. This would probably need at least a 300Ah (@48V) battery bank to support this usage. Equivalent to approximately 12 x 12V 110Ah batteries, although 24 x 2V batteries would be easier to maintain. The regular replacement cost of the batteries will be a large ongoing cost! Big saving on ballast though!

 

The other part of the running costs which are not factored in is depreciation of the boat. A boat so unusual as this is likely to be worth only half what it costs to build as a used boat the day after it's put in the water!

[Graham Davis]

Having had another think about this; is the OP actually thinking about a holiday boat or a live-aboard, because although his "ideas" might by OK for a personal owner it probably wouldn't fit a hire market.

 

Caprifool, so how do you provide a simple method of providing hot and cold running water in a boat?

[RLWP]

 

 

Caprifool, so how do you provide a simple method of providing hot and cold running water in a boat?

 

5 litre bottle and a kettle - next

 

Richard

[Graham Davis]

Yeah, right, but not exactly practical for long term is it?

 

Most people expect to turn a tap on and get hot and cold running water.

[RLWP]

Yeah, right, but not exactly practical for long term is it?

 

Most people expect to turn a tap on and get hot and cold running water.

 

Oh, the decadence of modern society

 

Incidentally, I think the OP's idea is rubbish - what happens at 3:00AM when you go to the loo?

 

Richard

[ditchcrawler]

Oh, the decadence of modern society

 

Incidentally, I think the OP's idea is rubbish - what happens at 3:00AM when you go to the loo?

 

Richard

You use a torch to see and pee over the side or in the composting loo which I think he meant. Yes it's all possible, would I want it no. I have seen people living in small plastic cruisers with no engines in the Braunston area with a bit of blue sheeting over the back. So you can do it if you want/need to.

[RLWP]

You use a torch to see and pee over the side or in the composting loo which I think he meant. Yes it's all possible, would I want it no. I have seen people living in small plastic cruisers with no engines in the Braunston area with a bit of blue sheeting over the back. So you can do it if you want/need to.

 

I'm not sure which bit you don't want. To be clear, I don't want either extreme - a floating tent or a boat dependant on a techie powerstation

 

Richard

[bottle]

By the time the hybrid and the batteries to run the boat etc are fitted, there will not be any room for the composting toilet.

 

 

ps I think this is just an exercise in boat design, well I hope it is.

[Gibbo]

If hybrid drive was any good it would have taken over the car world. The fact is, it's been an abysmal failure. Why would it be any better in a boat?

 

In a car it only has to power the vehicle. In a boat you've got all your electric needs too. The yearly savings in diesel miight just keep up with the monthly battery replacement costs.

 

I don't think any clever sums and spreadsheets are needed. I reckon it's simply a non starter without even putting any thought into it.

[RLWP]

If hybrid drive was any good it would have taken over the car world. The fact is, it's been an abysmal failure. Why would it be any better in a boat?

 

<snip>

 

Because, like a car, you can recover all that power from the propeller by regenerative braking - oh...

 

Richard

[Chalky]

Fully agree with Gibbo & RLWP.

Having spent a considerable amount of time working on hybrids for road use they only work due to the recovered energy which means city driving with lots of stop start. For long distance driving they're a lot worse since you've got to carry the extra battery and motor weight which affects fuel economy and CO2. I looked at converting our boat to electric drive however the overall efficiency was poor due to the power conversion and storage losses. There's a reason why most vehicles are parallel hybrids (direct connection possible between engine and wheels) rather than series hybrids (engine runs generator, electric motor powers wheels) and that's due to the losses. From all the work done one of the most efficient forms of personal transport is the bicycle!

 

Gibbo's not quite right about battery life. Using Lithium ion batteries it is possible to have a decent battery life. You'll just need to budget between £10,000 to £20,000 for the battery pack and also the engineering costs for the development of a 1 off pack.

Edited November 13, 2012 by Chalky

[bottle]

What is the life of Lithium Ion when used in a hybrid.

 

If and this is only a guess for the sake of argument discussion, is 15 years and taking Chalky's figures (average £15,000) the batteries will cost £1,000 per year

[Chalky]

Depends. There are a number of business models for the batteries. Some companies sell the batteries with the car, others lease the battery. The battery life depends very much upon battery chemistry (there are hundreds of types), usage and how its been treated. For hybrids it isn't so much of an issue since the battery management system can inhibit electric drive until the battery is charged and so protect it. In a pure electric vehicle this can't happen...

[Caprifool]

Nice old fashioned hand pump over a Belfast sink?

 

 

At home I have a hand pump out on the well and carry water in the kitchen in two buckets. I use a ladle to fill the kettle. Easy! Low tech and cheap.

[RLWP]

Nice old fashioned hand pump over a Belfast sink?

 

 

At home I have a hand pump out on the well and carry water in the kitchen in two buckets. I use a ladle to fill the kettle. Easy! Low tech and cheap.

 

I hadn't realised Ibsen was writing about 20th century Scandinavia

 

Richard

[GSer]

Standard small (ish) modern diesel engine, Oil lamps, cassette loo and a multi fuel range style stove for heating and cooking. Job done!

[Caprifool]

Now, now.....this is the life I chose out of my beliefs. At least I'm living the way I learn, instead of just talking. And I'm fully aware it's not for everyone. But I'm amazed how helpless people are when there's no button to press or tap to turn.

[Gibbo]

Gibbo's not quite right about battery life....

 

He is, but he's considered two things you haven't...

 

Firstly...

 

Using Lithium ion batteries it is possible to have a decent battery life.

 

But for the batteries to be of any use for domestic use at the end of the day's cruising, they need to be fully charged (or twice as big again). This means they spend a good portion of their life standing fully charged, or being kept fully charged, and that wrecks lithium batteries (of all particular chemistries). In a hybrid vehicle they spend most of their life between 40% and 80% charged which is when they last the longest. If they were kept fully charged they wouldn't last at all. They would also make the regenerative braking system somewhat redundant.

 

Secondly, if you put a lithium pack in there, suitable to act as a domestic bank, it would cost so much it would never, ever, pay for itself out of the fuel savings.

 

What is the life of Lithium Ion when used in a hybrid.

 

If and this is only a guess for the sake of argument discussion, is 15 years and taking Chalky's figures (average £15,000) the batteries will cost £1,000 per year

 

They last as long as they do because they are not kept fully charged. Keeping lithium batteries fully charged knackers them (the opposite of lead acid). Kept fully charged they are a joke.

[bottle]

The answers are as I expected.

 

Thank you