JumbleDuck
Well-Known Member
Isn't that comparing exhaust emissions of ships and cars? Not really relevant to the issue of watercourse pollution from anti-fouling, tank cleaning, sewage and so on.
USA banning copper-based antifouling
- Thread starter Bobc
- Start date
Isn't that comparing exhaust emissions of ships and cars? Not really relevant to the issue of watercourse pollution from anti-fouling, tank cleaning, sewage and so on.
ltcom
Well-Known Member
You credit the bbc with supplying facts?
https://www.forbes.com/sites/realsp...ion-is-now-the-biggest-polluter/#4bc079f61a19
states:
"In fact, one huge ship produces the same amount of cancer-causing chemicals as 50 million cars."
Most people know that once out of site of land these ships switch over to burning the most unrefined oil possible.
wikipedia:
Emissions from ships have a much more significant environmental impacts; many ships go internationally from port to port and are not seen for weeks, contributing to air and water pollution on its voyage.
Transport mean Passengers Emissions
(g CO2/km*pax)
Small car 4 42
Big car 4 55
Ship – 245
NormanS
Well-Known Member
Yes, and very few cars use antifouling. I think someone is trying to change the subject.
lpdsn
Well-Known Member
So having 300,000 articulated lorries heading overland from China would be an environmentally friendly policy. Interesting.
newtothis
Well-Known Member
Until 2020, when new IMO rules mean no more high-sulphur fuel can be used. Latest containership orders are having LNG tanks installed to reduce emissions. In terms of emissions per tonne/mile, shipping is actually relatively clean.
Triassic
Well-Known Member
Slightly off topic but I had this daft idea that a super tanker must be the ideal candidate for electric propulsion having all that deck space for solar panels. I was so wrong........ they would need somewhere in the region of half a million square meters of solar panel, and unfortunately they seem to only have half that in deck area........ When you look at these things the figures are frightening, 100,000hp burning 1,660 gallons of fuel an hour, or roughly 103 gallons to the mile!
ltcom
Well-Known Member
Yes, and very few cars use antifouling. I think someone is trying to change the subject.
No.
The USA is trying to ban anti-fouling on leisure boats.
What about the ships? What are they painted with?
So messing with leisure boats is a drop in the ocean.
ltcom
Well-Known Member
can you supply the source of your data for that please?
Tomahawk
Well-Known Member
If it was a 250,000 tonne job that equates to 0.000412 gallons for each tonne moved a mile.
Kelpie
Well-Known Member
Nobody suggested that.
If we're still talking AF, a ban on copper doesn't mean a ban on shipping. At worst, it means lots of work for divers. And more likely, investment in low-friction coatings and/or ultrasonic systems.
Kelpie
Well-Known Member
Curious. What efficiency level did you assume for the panels? Thy are improving all the time. And what cruising speed?
Daydream believer
Well-Known Member
Daydream believer
Well-Known Member
Personally speaking - considering how often i loose my phone - I could do with a far higher Search & Rescue for my phone even at the risk to the atmosphere
Last edited:
Triassic
Well-Known Member
I make no claim to know anything at all about the technology involved.... I just googled Supertanker, found they had around 100,000HP (75,000KW) which burns 1660 gallons an hour at 16 knots, and about 250,000m2 of deck space, then I googled solar panel size and found all sorts of measurements but they seemed to average out around 7m2 per KW, so 7x75,000 is just over half a million....... All really rough figures only looking for ballpark guide to practicality, and it suggests the idea is a long way off working, and that's before you factor in sailing overnight and on rainy days....... I'd be delighted if I'm miles out and it's feasible, but that then leaves the question why don't they do it. I would have thought burning the cargo is never a good business model?
savageseadog
Well-Known Member
The point about leisure craft v heavy shipping is that leisure craft generally remain with many others in one location near the coast for very long periods. Pollution will concentrate in marinas and mooring areas, Ships on the other hand will spend most of their time at sea.
newtothis
Well-Known Member
You can calculate it here for various ship types: http://www.martrans.org/emis/
Re: solar, there are a large number of trials, prototypes being worked on by engine makers and others, as well as looking at alternative fuels and other new technologies.
The shipping industry is well aware of its environmental impact and is being regulated quite heavily by IMO. Ships must now have ballast water treatment systems, SOx is being regulated from 2020. CO2 emissions are the next big thing, and the industry is wary of local regulations, e.g. EU placing controls on before international standards are established.
There is also a desire to be seen as green as possible. Some of this, no doubt, is greenwashing, but the point is that shipping is not a big amorphous industry dedicated to pumping toxins into the environment.
JumbleDuck
Well-Known Member
As I recall the argument about TBT antifouling, large ships spend most of their time moving and outwith coastal waters so they need relatively little antifouling and their leachate is spread across huge areas. Leisure boats in general spend almost all of their time in one place and the rest of it in shallow water near other leisure boats, so they need a lot more antifouling and the leachate is more concentrated, so overall they have a far greater effect.
Daydream believer
Well-Known Member
So based on the assumption (& we all know definition of assumption !!) that most plastic starts off near the coast how does a lot of it end up in a large area in the middle of the Pacific miles from the coast? Currents !!
ie.. Does that not suggest that contamination eventually gets concentrated to specific areas - not necessarily coastal, from where it started off.
I can accept that paint contaminate is distributed about the sea bed differently to floating debris, like plastic, but at sea the contaminate may never reach the sea bed. Therefore, like plastic, may well become concentrated in selected areas.
I further see no defence in the argument that the fact that contamination is spread over a wider area makes it more acceptable.
Rather like the old practice of piping untreated effluent further out to sea. (I found that unacceptable as well.) The fact that it is untreated & the fact that dumping it further out is supposed to make it cleaner. It is still s..t. (I believe that is no longer allowed by EU rules but the principle still applies.)
JumbleDuck
Well-Known Member
Good question. I think the issue with plastic is that it floats and remains as plastic on the surface. I'd expect dissolved material to behave very differently, since vertical convection and diffusion can spread it out.
Spreading it over a wider area may reduce the effects to a negligible level. To take your example of sewage, dumping a whole town's worth into a bay generally had nasty effects, but spread it over a much wider area and natural processes can handle it very easily.
newtothis
Well-Known Member
See also, tanker spills. Drop a few thousand tonnes of oil in the deep blue and wave action will quite soon return it to carbon molecules. Spread it over a sensitive shorefront and you get lots of dead things with big eyes that play badly in the media. But even there, nature will take its course and clean it up. Biggest f'up was steam cleaning the beaches in Alaska post Exxon Valdex, which stripped them of all life for years.
On the other hand, metals and complex chain compounds tend to hang around longer and do nastier things.