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  1. #41
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    Quote Originally Posted by John100156 View Post
    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....


    The car number was just to compeare/scale it. You know in Norway we have ice on the lakes!

    Easyest way to calculate is fulconsumption l/h *2.7kg co2/liter If you know the boat speed you divide!

    Question ! You are talking gallons? Is that 3.8liters or 4.5liter?

  2. #42
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    Please read my post #36 above! I use 2.67 but 2.7 is fine.

    I was talking of litres so not sure where the UK/US gallons bit came in?

    Also, you can not just divide the boat speed, you can only divide the litres of fuel consumed per hour by a particular boat by 2.7 to get the CO2 emission rate!

    Anyway, I'm off now - but ULYDEN welcome to the forum and to this debate!

    SEALINE F43 - CORAL RAE

  3. #43
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    Quote Originally Posted by John100156 View Post
    Please read my post #36 above! I use 2.67 but 2.7 is fine.

    I was talking of litres so not sure where the UK/US gallons bit came in?

    Also, you can not just divide the boat speed, you can only divide the litres of fuel consumed per hour by a particular boat by 2.7 to get the CO2 emission rate!

    Anyway, I'm off now - but ULYDEN welcome to the forum and to this debate!


    I did not understand the formula in post 8!

    I fully aggree with your post jonn! Noboddy are running at maximum power konstant! You have to calculate the effektive power! Im also off!

  4. #44
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    Quote Originally Posted by xtiffer View Post
    As they don't even realise that CO2 rises after temperature rises
    one can hardly expect them to figure anything out.
    Try watching this for an alternative view:
    http://video.google.com/videoplay?do...70191369613647
    Wow - great link, thanks. I hadn't seen that.

    Puts all the AGW bollox into perspective.

  5. #45
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    Default Co2 emission figures

    No doubt a dumb question: Are the figures for the amount of co2 in the exhaust fumes corrected for any co2 contained in the air which is drawn in to the engine?

    John G

  6. #46
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    Quote Originally Posted by Jegs View Post
    No doubt a dumb question: Are the figures for the amount of co2 in the exhaust fumes corrected for any co2 contained in the air which is drawn in to the engine?

    John G
    No, not a dumb question, although it's difficult to accurately quantify.

    The ambient level of CO2 in the air currently ranges between 300 to 400 parts per million, so it's generally ignored for stoichiometric combustion calcs. The following graph indicates changing levels:



    When we design CO2 controlled ventilation systems, we usually use the 400ppm figure. So 10,000 litres of ambient air contains only 4 litres of CO2!

    SEALINE F43 - CORAL RAE

  7. #47
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    Quote Originally Posted by Jegs View Post
    No doubt a dumb question: Are the figures for the amount of co2 in the exhaust fumes corrected for any co2 contained in the air which is drawn in to the engine?

    John G

    Unless you have an exhaust leakage the CO2 level in the air is about 0.03%.

    If the boat engine had an EGR (exhaust gas recirculation) system the CO2 concentration is higher and Oxsygen is lower!

    Marine engine normaly dont have egr because of the sulfur in the fuel!

    Nox levels goes down also with EGR! 10% egr rete is 20-30% reduction in NOx level!

  8. #48
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    Quote Originally Posted by ulyden View Post
    Unless you have an exhaust leakage the CO2 level in the air is about 0.03%.....
    Mmmm 0.03% as you may know is 300ppm (that is 3 hundredths of 1%) - the estimated atmospheric concentration around the year 1910! Although I am sure it ranges, I would use 0.0375 or even 0.04, that is 375-400ppm nowadays!

    Anyway, we have deviated from the OP - so no more input from me in this regard - perhaps you should start a new Climate Change thread, should provoke an interesting debate between power and sail!

    Runs for the hills......

    SEALINE F43 - CORAL RAE

  9. #49
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    Default CO2 - another question.

    Thank you for your informative replies to my previous question. May I try another?
    Not boating, therefore I shall understand if it is ignored.
    Do people contribute to CO2 in the atmosphere simply by breathing/processing food?
    Reason for query - has third world population increase caused any of the extra gas.

    Hopeful thanks,

    John G

  10. #50
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    The simple answer (best one I can give) is that breathing and eating food just recycles CO2 already in the air, it doesn't change the level up or down. The CO2 is going through a constant cycle of being fixed (as carbon in cellulose, protein, etc.) by plants then released as CO2, CH4 etc by animals when the plant's eaten. I don't know whether the vast number of humans on the planet means that there are more animals alive today than ever before but given they all eat food that's ultimately come from plants, the equilibrium level in the atmosphere shouldn't have changed. Although maybe the recycling is happening more quickly?

    Felling forests (that lock away large amounts of carbon) will cause an increase in atmospheric CO2 so a larger human population undoubtedly has had an effect. Someone might have a reference as to how big this affect is? All those humans contain carbon as well - how much carbon is locked up in the human population!?

    The vast majority of the 35% (or so) increase in atmospheric CO2 observed since pre-industrial times is undoubtedly down to 'new' (or is that old?) CO2 entering the atmosphere due to the burning of fossil fuel. The carbon in oil, gas and coal has been locked away from the atmosphere for millions of years meaning that prior to about 350 million years ago atmospheric CO2 must have been much higher than it is today.

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