Astonishing two stroke outboard stats

dylanwinter

dylanwinter

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www.keepturningleft.co.uk
if it is true then it is amazing


http://www.kimointernational.org/Web...s/RESL102D.pdf

"Two-stroke engines used by many pleasure boats are a major source of hydrocarbon and
other toxic emissions in coastal areas. The high emissions from traditional two-stroke
engines are caused by the design of the motor. Twenty to thirty percent of the fuel and the
added oil that these two-strokes use are emitted unburned directly into the water. At low
speeds, up to 40 percent of the fuel entering a cylinder might escape unburned while at the
most efficient operating range eight percent of the fuel is expelled as exhaust. A one-hour
ride on a boat with a 10-horsepower traditional two-stroke engine emits the same amount of
hydrocarbon pollution as driving a modern automobile 40,000km (25,000 miles)."

.....http://www.kimointernational.org/WebData/Files/RESL102D.pdf....



and a few others for you

http://www.dep.state.fl.us/air/emiss...-Factsheet.pdf

http://www.ukmarinesac.org.uk/activi...ion/r03_01.htm

http://www.unep.org/transport/pcfv/P...okeEngines.pdf

http://www.sdearthtimes.com/et0897/et0897s2.html

http://www.epa.gov/region2/cleanmari...7_04report.pdf
 
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Strange that only one of the inks works. Modern 2-strokes running on low ash synthetic oils should not be compared to Seagulls just as the emissions from an Ariel Arrow are quite different from those from a Yamaha RD250. 2-strokes are less efficient than four strokes because the gasses in the engine continue to expand in the exhaust tract to scavenge the cylinders. I think trying to compare a trip out under 2-stroke power with a 25000 mile trip in a modern car is alarmist nonsense. Emissions and pollution are not solely hydrocarbon in nature, you can't ignore the CO and CO2 unless you're playing silly bugers with the stats.
 
There is little point these days of having 2 stroke outboards which are too large to chuck in a locker. The great advantage of small 2 stokes is that they can be put away in any position without the worry of oil spilling out. With 4 strokes there is no hassle of mixing the oil so it makes sense to have quieter easier larger 4 stoke outboards.
The emissions from small 2 strokes have now been overcome by the superb electric Torqeedo motors.
 
dylan said:
There is little point these days of having 2 stroke outboards which are too large to chuck in a locker. The great advantage of small The emissions from small 2 strokes have now been overcome by the superb electric Torqeedo motors.
Click to expand...

I suppose that depends where you are getting the electricity from for the Torqueedo. Large diesel at low revs to charge a battery isn't good. Charging from your own solar panels would be better (though you'd need a lot of surface area).

I couldn't read the evidence either but I would like to see how this was derived:
"A one-hour ride on a boat with a 10-horsepower traditional two-stroke engine emits the same amount of
hydrocarbon pollution as driving a modern automobile 40,000km (25,000 miles)."

That would mean a 2.5HP is roughly in the ball-park of pollution from a car driving around 6,000 miles.
I note that the term is "hydrocarbon pollution", perhaps they are simply comparing unburnt fuel in both cases. The car will have a relatively tiny amount of unburnt fuel vs. 2-stroke and also has a much more sophisticated system for removing unburnt fuel & crank vapours. A comparison of CO and other pollutants would probably not yield as large a difference.

Not saying it is good, but could be the pollution from a tiny outobard is not quite as bad as it seems. Hence the reason I'd like to see the evidence. I'll be away for a week or so and will try to check on the links if I get the chance.
 
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dylanwinter said:
if it is true then it is amazing


http://www.kimointernational.org/Web...s/RESL102D.pdf

"Two-stroke engines used by many pleasure boats are a major source of hydrocarbon and
other toxic emissions in coastal areas. The high emissions from traditional two-stroke
engines are caused by the design of the motor. Twenty to thirty percent of the fuel and the
added oil that these two-strokes use are emitted unburned directly into the water. At low
speeds, up to 40 percent of the fuel entering a cylinder might escape unburned while at the
most efficient operating range eight percent of the fuel is expelled as exhaust. A one-hour
ride on a boat with a 10-horsepower traditional two-stroke engine emits the same amount of
hydrocarbon pollution as driving a modern automobile 40,000km (25,000 miles)."


and a few others for you

http://www.dep.state.fl.us/air/emiss...-Factsheet.pdf

http://www.ukmarinesac.org.uk/activi...ion/r03_01.htm

http://www.unep.org/transport/pcfv/P...okeEngines.pdf

http://www.sdearthtimes.com/et0897/et0897s2.html

http://www.epa.gov/region2/cleanmari...7_04report.pdf
Click to expand...

Surely in that case the fuel consumption on a two-stroke would be 20 to 30% worse than on a 4 stroke. That might work for an out of tune Seagull compared to the latest 4-stroke but I can't see it comparing a 3.3 Mariner to a similar size contemporary 4-stroke.

The first sentence is just garbage. What does "major source" mean? 2-strokes are hardly used in some areas - are they suggesting that 2-stroke engines on pleasure boats are major source of pollutions in the Alaskan coastal areas? The trouble is, once someone puts a stupid throwaway comment like that in I tend to doubt the accuracy and provenance of the rest of the piece. The final sentence is no better. Some modern automobiles use fairly primitive engines. I dread to think what pollution full-throttle acceleration followed by sharp braking and then full-throttle again, etc. over 25,000 miles in a big heavy motor would produce but I'll bet it's more than 1 hours boating in 10 hp two-stroke at a nice cruising speed in a well-balanced rig in flat water. As for traditional - what the hell is a non-tradional design? Evinrude ETEC or similar? The smallest I know of there is about 40HP I think.

I'd agree that Seagulls (and other out-of-date and usually out-of-tune motors) shouldn't be in use anywhere in an ideal world but to pretend this has made a lot of difference in most of the world seems ludicrous. There's a lot of things they could sort out before worrying about this.
 
I used to own a boat with a 250 hp 2-stroke. The oil slick was not readily apparent when underway, but the sheen on the water when idling at the dock could not be ignored.

shiny_new_motor.jpg


In the United States, 2-strokes are banned on many freshwater lakes. On some lakes, a distinction is made between older 2-strokes and newer direct-injected 2-strokes (Mercury Optimax and Evinrude E-Tec). There are no such restrictions that I know of on saltwater, and boats with older 2-stroke engines remain common. I know many people who prefer the older 2-strokes because they are dependable and easy to maintain. The newer direct-injected 2-strokes don't share these attributes, and they seem to be losing market share. I went to a boat show recently and didn't see a single boat offered with a 2-stroke engine.
 
Actually there are two-stroke engines of new generation, having even less emission and better economy than 4-strokes. Quite simply efficient direct injection deals with combustion problems; the injection must be made in more complicated manner but computer control is no problem nowadays. Only, I'm afraid, computers and salt water might not mix well... Guess only Yamaha uses mechanical injection pump now. Incidentally, american engines had injection system not suitable for water use and this was main reason for OMC bankruptcy.

All major producers are working on the concept now, since it offers a lot better parameters with simpler construction then 4-stroke, we may see interesting things in future.

Not to mention two-stroke diesels, which I remember used in boats - lightweight, simple, no vibration, twice the power. At least those had no electrics. Well liked they were, some fishermen here kept to them for long time. Were robust and more economical actually. Whatever happened to them... But also coming back :)
 
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What's shocking is the hydrocarbons used driving to the boat to go sailing, if we all stayed at home and played with a pond yacht in the bath we'd emit no hydrocarbons.
 
It's our duty to let small amounts of oil escape into the environment.
There are bugs that live on oil and they will all die of starvation if we don't.
If all the little bugs die there won't be any about to deal with significant spillages when they happen.
 
true

Lazy Kipper said:
What's shocking is the hydrocarbons used driving to the boat to go sailing, if we all stayed at home and played with a pond yacht in the bath we'd emit no hydrocarbons.
Click to expand...

that is true

but if the stats are true - one hour with a ten hp equivalent to 25,000 car miles.....

and replacing the seagull is such an easy and painless win for the place where we sail our boats

and I am a hypocrit -

my boat also has a sea toilet - I am a bad man (probably)

KTL is clocking up about 4,000 car miles a year

or around a tonne of co2 in the one litre Polo -not as much as a trip to the USA or a skiing holiday - but I am guilty - I am a craven hypocrit


however, driving the car is not pouring, injecting and spraying unburned hydrocarbons straight into vulnerable inter-tidal environments

I apologise at the offense caused by suggesting that to use a seagull is a bit like urinating in your own kitchen

would anyone care to come up with a more sanitary simile?


I myself am extremely bored with re-iterating the argument in as many different ways as I can that it is not about co2 or global warming or the burden of re-cycling old engines and manufacturing new ones. All excellent points but nothing to do with the one I am trying to make.

it is about the fact - and it is a fact for goodness sake - that old two strokes in general and seagulls in particular pour pollution straight into the rivers, lakes, canals and estuaries where we sail our boats, watch the birds, swim our dogs and our children, eat the shellfish and enjoy the purple flowers across the salt marshes.

if one bloke decides that it would be better to hang up the seagull then it will be worth it

if on the other hand blokes continue to say that they will carry on doing it regardless of the evidence because they like it....

well that makes me sad... and we deserve the good kicking that Hugh Fernely is going to give us


Dylan
 
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Topcat47 said:
2-strokes are less efficient than four strokes because the gasses in the engine continue to expand in the exhaust tract to scavenge the cylinders. I think trying to compare a trip out under 2-stroke power with a 25000 mile trip in a modern car is alarmist nonsense. .
Click to expand...

The problem with 2 strokes is that the inlet port and exhaust port are open at the same time so you get some unburnt fuel pumped into the exhaust together with the lube oil. They are also less efficient simply because they have a lower combustion ratio. In comparison a modern car with a catalyst is almost at the point where the wir out of its exhaust is cleaner than what goes in through the air filter, depending on whether its running in Shanghai or the wilds of Canada. But I agree with you that the comparison is a bit silly - you cant use a car for what you use a 2 stroke outboard to do.
 
wotayottie said:
The problem with 2 strokes is that the inlet port and exhaust port are open at the same time so you get some unburnt fuel pumped into the exhaust together with the lube oil. They are also less efficient simply because they have a lower combustion ratio. In comparison a modern car with a catalyst is almost at the point where the wir out of its exhaust is cleaner than what goes in through the air filter, depending on whether its running in Shanghai or the wilds of Canada. But I agree with you that the comparison is a bit silly - you cant use a car for what you use a 2 stroke outboard to do.
Click to expand...


but there is a really good alternative to a two stroke outboard

it is a four stroke outboard.

If those stats are correct.....and I hope that some of the sharp minds on here will take a good look at the data and come back to us ... then continueing to use a two stroke when there is a perfectly good alternative would seem to be really rather irresponsible

Dylan
 
Oil (and gas) are naturally occurring in the world. Mostly, but not always trapped down deep in the earth. Look at boggy areas, and you will often see an oily sheen on the water. Nothing to do with 2 strokes, 4 strokes, or any other kind of strokes.
However, if you really feel strongly about it, don't use an IC engine at all. Go back to walking and rowing.:rolleyes:
 
dylanwinter said:
but there is a really good alternative to a two stroke outboard

it is a four stroke outboard.

If those stats are correct.....and I hope that some of the sharp minds on here will take a good look at the data and come back to us ... then continueing to use a two stroke when there is a perfectly good alternative would seem to be really rather irresponsible

Dylan
Click to expand...

Dylan,

If you wanted to be pedantic - you would row.
 
Once upon a time we had dinghies that would row beautifully silently in a gentle parody of gym membership whilst working up a thirst en route to some waterside pub or drifting silently past early morning bird calls.

A far cry from the energy lavished on pushing the car, boat engine, inflatable engine..to get that same pint of beer, and deep six all the facts about the noise nuisance and pollution in the act

Seagulls live ( on) in sheds. How about a government 'Pair of Green Oars' discount scheme?
 
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I,m really BAD!

I have 2 Mercury 3.3 outboards 2 stroke 100:1 mix.So I would be thought a double polluter! In fact one was used once ten years ago,then decomissioned and has lived in a wardrobe ever since.Occasional pull of the cord to see if rotation is still ok.The other lives on the boat and was not used at all last season!So I have little to confess except that I have saved the production pollution of manufacture of two 4 strokes whose oil spillages would outweigh any potential benefits!
 
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