So how much CO2 do motorboats emit?

[VicS]

Er maths may not be my string point

150 hours at 8.1 litres per hour = 1215 litres

Multiply by 0.85 gives 1032 kg of fuel

every 1 kg of fuel proiduces 3.16kg CO2
so thats 3263 kg or 3.263 tonnes CO2 PA for the boat

Car:
10,000 km at 233g per km = 2,330,000 g = 2.33 tonnes.

Total for car and boat 5.6 tonnes CO2 PA

No wonder the end of the planet is within sight!

Get sails for boat, very very much smaller car, buy calculator!

 

[Lakesailor]

Nah. Rev up the V8s. Obama has organised it all so that it'll be OK.

The Yanks and Chinks have done a deal. We aren't included, so bods to them. We will plough our own furrow.

Oh! And take down all those useless windmills.

 

[Major Catastrophe]

I think you are lying, I don't recall any attempt to make me cycle 95 miles to work, or I would have paid attention!

It was our Norm who diddit.

 

[oldgit]

"No wonder the end of the planet is within sigh"

Cripes..err any actual 2 x 400hp average flybridge owners care to stick their heads over the top of the trench with some fuel figures ?

 

[JohnRob]

Do you think I can claim my KAMD300s are much more friendly from a CO2 perspective as most of the diesel ends up as unburnt carbon soot on the transom?

 

[John100156]

You know the fuel consumption of your boat

use a figure of 0.85 kg per litre as the density to convert litres to kilograms

take the info from Wikipedia at face value, use an average chemical formula of C12H23 and work it out. (you learnt how to do that when you were about 13)

I'll give you a start like they do in modern dumbed down GCSE exams

the equation for the burning of diesel fuel is

4 C12H23 + 71 O2 —› 48 CO2 + 46 H2O​

The RAM of carbon is 12, the RAM of hydrogen is 1, and the RAM of oxygen is 16

Hey,

Where has all that lovely Nitrogen gone? Come on VicS, remember your stochiometric (or not) combustion..... With unburned components in the exhaust gas, such as C, H2, CO, the combustion process is uncompleted and not stoichiometric .

The combustion process can therefore be expressed as:

[C + H (fuel)] + [O2 + N2 (Air)] -> (Combustion Process) -> [CO2 + H2O + N2 (Heat)]

where

C = Carbon
H = Hydrogen
O = Oxygen
N = Nitrogen

 

[John100156]

OK - so heres my best guess:

Specific Energy Content: 11.8 kWh / kg fuel
Specific CO2 Emission: 0.24 kgCO2 / kWh
Specific Carbon Content: 0.86 kgC / kg fuel

 

[poltergeist]

Here you go. Gordon Brown´s infamous 50 days to save the planet speech:

http://www.number10.gov.uk/Page21033

You will note he claims that if we don't act 35,000 people a year will die in heatwaves in Britain every summer, and



Hence the "50 days to save the Planet" headlines.

Enjoy reading it.

Is he not a part of the same government that was rambling on about WMD's in iraq. They are a shambolic bunch of crooks full of misinformation & lies. No wonder the country is in such a state - they are solely responsible!

I'm ranting ..... time to breath & count to 10. Or maybe 100 !

 

[VicS]

Where has all that lovely Nitrogen gone?

No where. Just goes in with the oxygen , comes out again with the CO2 and water vapour.
Makes no difference to calculating how much CO2 is produced from a given volume of diesel fuel.

Before any body mentions NOx I not getting involved with that. Guys at the other end of the office were the combustion experts!

 

[jfm]

I make it that the mass of CO2 is 3.16 times the mass of fuel. Correct?

Yup fatlady, the mass of co2 is 3-and-a-bit times the mass of fuel, because of the mass of the oxygen molecules taken from the air. That was all set out in my post on "should you run engines for 20mins in winter", a few weeks ago

 

[Cliveshep]

No not quite .

look again at the equation 4 C12H23 + 71 O2 —› 48 CO2 + 46 H2O

From that you can deduce that you stick in 4 moles of diesel fuel AND 71 moles of oxygen and get out 48 moles of carbon dioxide and 46 moles of water which means that, using the relative atomic masses given earlier, 668g of fuel plus 2272 g oxygen go in and 2112g of carbon dioxide plus 828g of water come out.

Total mass going in is 668 + 2272 = 2940g
Total mass coming out is 2112 + 828 = 2940g

Therefore total mass going in = total mass coming out and the law of conservation of mass is obeyed

"Bloody hell", as you say, ... you were taught all this when you were 13 or 14!

School? Taught? Things might have been mentioned I suppose, that was nearly 50 years ago. Was I supposed to learn something there then?

I like my simple sums better, more comes out than goes in. Bit like political hot air in Westminster I suppose.

 

[nonitoo]

When I last heard, the Chinese were opening a new coal fired power station, on average, every two weeks.

Soon counterbalance that threat by reducing my fuel consumption by 10% and recycling my paper and plastic - that'll show them !!!

After Copenhagen it looks as though we are all off to Hell in a handcart.

Tom

 

[Bobobolinsky]

When I last heard, the Chinese were opening a new coal fired power station, on average, every two weeks.

Soon counterbalance that threat by reducing my fuel consumption by 10% and recycling my paper and plastic - that'll show them !!!

After Copenhagen it looks as though we are all off to Hell in a handcart.

Tom

What do you think they are burning in their powerstations ;-)

It might not be this thread, but someone asked what about newer engines? Well newer engines, are good for cars where changing revs, gears and gradients are the order of the day, but on the flat at constant revs are not really any better than the old engines.
What about bio-diesel? Bio-diesel actually burns more efficiently in a diesel engine, however in doing so, it produces significantly more Nox.

 

[Philiz]

Given that our Great Leader has pronounced that we are all going to burn in the fires of damnation unless we plant a windmill in our garden and ride a bicycle to work, is it time we motorboaters at least gave a thought to how much CO2 our pride and joys emit?
So anybody got a clue how much CO2 the average 40ft flybridge boat sporting 2 x 400hp diesels emits per nautical mile at cruise speed? How about at displacement speed? Are modern electronically controlled marine diesel engines a lot better than clunky old mechanically fuelled ones?

I don't know, and to be honest, I don't care. I'm sick and tired of hearing about global warming, or is it climate change now. Since being a kid I've seen numerous stuff in books and on the TV showing us how the climate has changed through the ages and how it's affected the Earth. It's nothing new, it's natural progression. Bloody good excuse for hitting us with more taxes though.

 

[rafiki_]

In histry and geogfry at school, I don't remember there being too many mobo's either during the ice age, or the subsequent heat waves. If the Romans grew grapes in the early 00's, which gas guzzlers were the culprits?

I wish people would stop implying that climate change is man-made. I'm sure we actually don't help much, but it is not a man made phenomenum.

Also, when the Chinese and Indians all own cars, our problem here will be affording fossil fuels. They will use most of it.

Our challenge is to find alternative fuels and adapt to climate change.

That's why I bought my boat, for the heatwaves that accompany climate change.

 

[John100156]

OK – here are my final thoughts, to answer the OP:

My brief research indicates that most diesel engines will produce between 2.4 to 2.8 kg CO2 per litre of fuel burned. The figure I would use for newish boats would be say 2.67 kg CO2 per litre of diesel fuel burned.

So, for my boat, using twin Volvo KAD300’s (210kW/285hp) the fuel consumption (not at full prop load) is given by Volvo at:

Hence for a typical prop load and engine speed of 2600 rpm, my boat will consume 25 litres of diesel per hour, per engine. Therefore releasing: 25 x 2.67 = 66.75 kg CO2 per engine per hour at 2600rpm.

TOTAL: 133.5 kg CO2 per hour for twin engines at 2600rpm.

Now the OP was asking about 400hp engine boat. Well using the data for a Volvo D6 320kW (435hp) as follows:

For a typical prop load and engine speed of 2600 rpm, it will consume 37 litres of diesel per hour, per engine. Therefore it will release: 37 x 2.67 = 98.79 kg CO2 per engine per hour at 2600rpm.

TOTAL: 197.58 kg CO2 per hour for twin engines at 2600rpm.

So, from the above, as a very broad brush rule of thumb guide, you could say an engine uses around 0.22 kg CO2 per engine hp!

A 400hp twin engine boat at cruising speed will therefore release: 176 kg CO2 per hour.

Using the 2.67 kg CO2 per litre of fuel burned equates well with VicS assumption of 3.263 tCO2 released per annum for a boat running 150 hours at 8.1 litres per hour = 1,215 litres x 2.67 = 3.244 tCO2 per annum.

All as clear as mud - any questions:

 

[Deleted User YDKXO]

Thanks, John. That seems to be of the same order as VicS has calculated and I think surprisingly low given that we drive gas guzzling gin palaces. Of course it's only low because of the relatively few running hours we do compared to a car. Even so, we could equally argue that when we are on our boats, we can't drive our cars so motorboating could even be viewed as 'green'. OK, thats stretching the point a bit

 

[John100156]

Not to mention the fact that our houses will then be using far less energy in the form of heating, hot water and lighting when we are away and on the boat, a significant carbon off-set!

When engines are running, our boats also drive electrical generators (alternators) that charge our batteries, which power our lights, and the waste heat from the engine also heats the hot water - not to mention solar power and wind generation.....!

I am sure it will not be too long before we are pulling into our energy (not fuel) stations to fill up simply by un-plugging our spent standard hydrogen fuel cell, placing it in the energy receptor in what was the fuel pump, unplugging a new charged unit and placing it back into our car/boat!

Then we will all end up like......

 

[ulyden]

CO2

OK - so heres my best guess:

Specific Energy Content: 11.8 kWh / kg fuel
Specific CO2 Emission: 0.24 kgCO2 / kWh
Specific Carbon Content: 0.86 kgC / kg fuel

Specific Energy Content: 11.8 kWh / kg fuel this is ok!

Specific CO2 Emission: 0.24 kgCO2 / kWh : this is for heating

For a diesel engine this number is approx 0.22kgf/kwh*3.18kg CO2/kgf
= 0.7kg CO2/kwh

Specific Carbon Content: 0.86 kgC / kg fuel ok for diesel oil!

In this exsemple a boat with 800hp is produsing massive 800hk*0.735 *0.7kg co2/kwh ?= 411kg co2/h If the boat speed is 25knots the emission is 16kg co2 pr nautical mile! A car wil produse 0.2kg/kilometer or 0.37kg/ nautical mile (1852m)!

 

[John100156]

In this exsemple a boat with 800hp is produsing massive 800hk*0.735 *0.7kg co2/kwh ?= 411kg co2/h If the boat speed is 25knots the emission is 16kg co2 pr nautical mile! A car wil produse 0.2kg/kilometer or 0.37kg/ nautical mile (1852m)!

It depends of course on the fuel burn rate at the specified speed, and engine/boat efficiencies (see my calcs and fuel consumption graphs above), but hey, if you can afford 800 horses you can probably afford to Carbon offset!

Anyway, not sure how far a car would go on water, we are talking about boats here - horses for courses! Perhaps thats your answer, Carbon footprint of a horse is likely much less than a car and both can be used on the road! So, sell the car and buy a horse! But if you want to travel on water..... (Raggies to stay clear of this one!).

A large 67ft twin engined boat may burn say 300 litres per hour, that equates to 811kg CO2 per hour! Would I buy one if I could afford to run one? Yep....