Another place to put a ship's exhaust pipes

Discussion in 'Boat Design' started by Anthony Appleyard, Sep 9, 2018.

  1. Anthony Appleyard
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    Anthony Appleyard Anthony Appleyard

    I found this image on the web:
    Stock Photo - stern of a ship with the exhaust pipe of the diesel engine https://www.alamy.com/stock-photo-stern-of-a-ship-with-the-exhaust-pipe-of-the-diesel-engine-168779941.html

    Accompanying text says "stern of a ship with the exhaust pipe of the diesel engine - Image ID: KPGGF1", so those four pipes are what they seem to be. Accompanying images seem to say that the ship is a container ship and thus big. I would NOT fancy having to come up to that ship close astern and its hot smelly blast from pipes a foot or more diameter when it was running its engines. Why can't they go on top blowing upwards out of the way?
    ~~~~~~~~~~~~~~~~~~~~
    What is the partly-submerged mechanism below each pair of exhaust pipes on that image?
     
  2. SamSam
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    SamSam Senior Member

    That's not a ship, it's a catamaran boat with maybe 12' beam and possibly jet drives. Ships don't have spray rails on the sides. The photo people mistakenly calling it a ship probably helps create a mental illusion that it is big.
     
  3. Anthony Appleyard
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    Anthony Appleyard Anthony Appleyard

    Thanks. But I saw a real example of antisocially-placed diesel exhaust pipes :: when I was younger, I scuba dived (I have got rid of my diving gear since); in Hurghada harbour I saw a diving liveaboard called Sir Cousteau, and on its flat vertical stern it has two diving ladders side by side, and two diesel exhaust pipes which blew straight-open-ended point-blank each through one of the diving ladders.

    I dived from a liveaboard diving boat there which had a square recess in the stern, and in that recess were the diesel exhaust pipe (whose end turned downwards) and the diving ladder; when coming out after a dive in no wind and the engine running, we were advised to keep our diving masks on and our mouthpieces in until we were out of the recess and well up on deck.
     
  4. SamSam
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    SamSam Senior Member

    We went to Europe in the '90s and all the semis (at least in Germany) seemed to have exhausts that directed the diesel fumes at the pavement and thus into you car when following a truck. I thought it was kind of rude and sort of ignorant as it really stunk up following cars. All semis in the US used stacks that shot it out over the top of the trailer and fumes were no bother. I'd get all patriotic when a US Army truck would be driving along and spewing all their exhaust up in the air where it's supposed to be.

    Close behind boats can be a deadly zone, like on the swim platform or even being towed in a tube or a float close to the transom. Regulations are usually a good thing.
     
  5. The Q
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    The Q Senior Member

    There have been many cases on the Norfolk broads recently where people runnning their engines / generators at moorings have poisoned themselves or their neighbours with carbon Monoxide, some deaths have occurred. It's on the increase as more and more people want all the comforts of home while out on a broads holiday. It looks like from next April all boats on the Norfolk Broads will have to be fitted with CO detectors.. Carbon monoxide killed boat death couple https://www.bbc.co.uk/news/uk-england-norfolk-36606918
     
  6. Anthony Appleyard
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    Anthony Appleyard Anthony Appleyard

    There is a law in Australia that all large diesel vehicles must have vertical exhaust pipes. I once even saw there a vertical exhaust pipe on a bus.

    I was in Coonabarabran (New South Wales outback) 18 nights in June/July 1984 to see the far south stars (astronomy).

    When I have seen lorries/trucks (in England) raising dust on building sites, most of the dust seemed to come from under the end of its exhaust pipe and not from under the wheels.

    Coonabarabran - Wikipedia https://en.wikipedia.org/wiki/Coonabarabran
     
  7. SamSam
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    SamSam Senior Member

    That's an advantage of the diesel stink, you know it's there. Gasoline, not so much.
     
  8. SamSam
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    SamSam Senior Member

    Busses here still direct exhaust at the ground and stink when you follow them. Some semis here have eliminated the stacks but odor doesn't seem to be a problem. Efficiency has improved so that might be it.
     
  9. goodwilltoall
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    goodwilltoall Senior Member

    Putting exhuast at transom has been done for years. I would have done it myself except it was easier to just draft vertically. Advantages of no soot/noise nearby plus opening up deck space for other uses make it appealing. Some even angle the pipes right into the water eliminating mufflers although with a small hole for antisuction ahead
     
  10. Anthony Appleyard
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    Anthony Appleyard Anthony Appleyard

    I once met someone who said that he liked diesel exhaust smell because it reminded him of boating holidays.
     
  11. Ike
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    Ike Senior Member

    Exhausts on the transom was and is still the usual place on small craft. However, in recent years larger boats, particularly houseboats, have been using vertical stacks to direct exhaust up and away from the boat. This change has come about because of carbon monoxide deaths on houseboats from exhaust trapped under the stern swim platforms, and from people swimming near the boat when the generator was running. Most of these were gasoline powered but the same method of getting exhaust away from the boat would work with diesels. Also, some efforts have been made to design boats with exhaust on the sides at or near the transom. This works well with boats that have a squared off cabin that tends to trap exhaust behind the cabin due to the station wagon effect.
     
  12. Squidly-Diddly
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    Squidly-Diddly Senior Member

    In SF bay area we had a rash of Public Service Announcements about not letting kids sit on transom due to how it traps CO, and that boat engines produce massive CO low ago outlawed and regulated in cars.

    Our dad told us kids we couldn't sit on the bow of the houseboat to skim our feet on the water, because if we fell it we'd get chopped by the prop, but we could sit on transom and skim, which wasn't near as much fun.

    Every couple weeks some old "classic" car will be next to you in traffic and it will make your eyes water, and bring back "the good old days". Yeah, I know CO is odorless, etc.
     
  13. Ike
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    Ike Senior Member

    I have had to deal with parents or other family members of some kid who has died from CO. That is not fun.
     
  14. SamSam
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    SamSam Senior Member

    Does carbon monoxide sink and form a sort of blanket around the boat? That's frightening because your impulse when having a problem breathing would be to swim to the boat and thus into the danger. Swimming away from the boat and the CO would be the opposite of instinct.
     

  15. Ike
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    Ike Senior Member

    No. It disperses into the air displacing the oxygen, but can be trapped in confined spaces with little ventilation. The CO poisonings with swimmers have been primarily by CO in exhaust being trapped under swim platforms (on houseboats) and people swimming near the stern of a boat while the engine or generator is running. For a while some young people thought it was a thrill to hang onto the swim platform on a boat while the boat was moving, and the were directly breathing the exhaust (as well as exposing themselves to the risk of prop strike). One young girl was overcome by CO when she tried to wash her hair in the cooling water coming out of the exhaust from the generator. But mainly it is a problem of people being poisoned while sleeping. They leave the air conditioning running (and the generator to run the A/C) and the exhaust gets sucked in by the A/C. Any breeze will blow it away, a well ventilated cabin will disperse it, and designing boats to reduce the station wagon effect also reduces it. Having airtight bulkheads between the engine room and the living accommodations keeps it out. Making sure there are no exhaust leaks in the engine room helps. Keeping the engines tuned up and running well also reduces CO. Modern computer controlled engines also reduce CO emissions. Most marine generators now are diesel. but there are still some gas powered ones and the manufacturer claims that when running properly it has zero CO. So there are ways to mitigate the problem.
     
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