Combining genset and main engine exhaust

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healhustler said:
Ted: I don't think I've got that 24" above the water line for the lifts.....more like 16-18", limited by the veranda sole. Still, that's a lot more than I had for the genset when it was mounted under the galley, which needed an anti-siphon that went through the galley sole and looped under the fridge. For all practical purposes, the joint exhaust should work, and I envisioned the genset exhaust tubed into the top of the main exhaust, just as you described.

I've gone this far and to great expense for this swap. I'll do the two separate exhausts as recommended, but since both the main and the genset exhaust exit on the port side, it only makes sense to exit them easily to the port transom. Many boat owners complain about genset exhaust exits on one side or another, especially when they are rafting. I really dislike the idea of two separate exhausts on one side of the stern, but....
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The reason ABYC "recommends" (is that better :) ) that genny exhaust not exit at the transom is due to the potential for CO poisoning for people on the swim platform. This standard was adapted after a USCG press release and a NIOSH investigation of generator related fatalities in house boats.
 
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Agree with that. If you have (or plan to install) a swim platform, genny exhaust is better at hullside.

Also, CO risk is WAY higher with gasoline gennies. Diesel does create CO, but much less. I don't think I've heard of any CO poisoning cases with diesels.
 
The problem with CO and diesels is that CO is cumulative and does not disperse from the blood for up to two weeks. Kids sitting on a swim platform over a long weekend can build up a significant amount of CO in their blood.
 
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Yesterday at the wildlife museum I volunteer at, I noticed a tank of C02 with a hose leading to a clear plastic box. That's a testimony to the gas's effectiveness.
 
RT, the point is C02 is an effective killer. I'd presume the reader can add 2 plus 2. :rolleyes: Sorry for the goof. Confused C0 with C02. Both deadly gases. :eek:
 
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markpierce said:
RT, the point is C02 is an effective killer. I'd presume the reader can add 2 plus 2. :rolleyes: Sorry for the goof. Confused C0 with C02. Both deadly gases. :eek:
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Neither one are deadly until certain thresholds are reached. The same holds true for most gasses including HCN. Trees love the CO2 you exhale Mark.
 
I got interested in CO poisoning about 10yrs ago when six people were found unconscious on a boat not too far from mine, cause - propane furnace produced CO.

A long time client (sailor but still a good guy), a professor of haematology at UofT gave me a brief education on the subject and this article has been on my website since then.

The table showing ppm required to cause a variety of health issues shows just how little of this stuff it takes to do serious damage. The really insidious aspect of this condition is that the symptoms mimic those of sea sickness.

Go ahead Rick, take your best shot, I can handle it :)
 
boatpoker said:
Don't know any boats that carry pure oxygen and the half life is irrelevant without oxygen once it's in your blood.
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I for one carry Oxygen and a demand mask on my boat. When you consider that most of us on this forum are.......well.......in or approaching the golden years, there are all sorts of events (like strokes and heart attacks) that the administration of Oxygen immediately will be of great value to the afflicted. It's also good for reducing the pain of the morning hangover. :rolleyes:

Ted
 
O C Diver said:
I for one carry Oxygen and a demand mask on my boat. When you consider that most of us on this forum are.......well.......in or approaching the golden years, there are all sorts of events (like strokes and heart attacks) that the administration of Oxygen immediately will be of great value to the afflicted. It's also good for reducing the pain of the morning hangover. :rolleyes:

Ted
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In an ignition protected environment I trust :)
My wife was on oxygen for a while last year. We had to take a course to get approved to have oxygen at home. One of the curious things they told us was not to use vaseline under her nose as there had been a number of cases of ignition burns and vaseline is flammable. They also told us no smoking at home and not to have in the same room as an open flame. Please don't argue this one with me, I'm just repeating what we were told.
 
boatpoker said:
In an ignition protected environment I trust :)
My wife was on oxygen for a while last year. We had to take a course to get approved to have oxygen at home. One of the curious things they told us was not to use vaseline under her nose as there had been a number of cases of ignition burns and vaseline is flammable. They also told us no smoking at home and not to have in the same room as an open flame. Please don't argue this one with me, I'm just repeating what we were told.
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Is this the Canadian health care system? A course is required to buy a life saving gas, but something as flammable as gasoline or dangerous to your heath as cigarettes requires nothing. :rolleyes:

All kidding aside, took an oxygen administration class 20+ years ago because of the business I'm in (scuba diving instruction and charters). One needs to be careful using oxygen on a boat. If you breath pure O2, you inhale 100% and exhale about 96%. Where that 96% goes in an enclosed boat is important. Sadly, we learned about using Vaseline during WW2 when bomber pilots had problems with it on their lips while breathing oxygen in flight.

Guess I agree with this post of yours. ;)

Ted
 
boatpoker said:
Don't know any boats that carry pure oxygen and the half life is irrelevant without oxygen once it's in your blood.
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The point was that your statement that it was cumulative and remained in the system for weeks is yet another example of "surveyor" horsepucky.

That absurd claim was one more of a long string of easily debunked statements made on this site that illustrate why any comment from a "surveyor" should be viewed with great skepticism.
 
boatpoker said:
Go ahead Rick, take your best shot, I can handle it :)
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Well, since you asked ... ;)

Let's see, you make an absurd statement then to back it up you link to an advertisement for your business in which you self publish an "article" that was evidently the source of the same ridiculous assertion.

Following your bizarre circular logic and version of physics and chemistry, a smoker would be dead of CO poisoning in about 2 days.

Here is a link that explains it in terms even a "surveyor" might understand:

Carbon Monoxide in Cigarettes - Carbon Monoxide Kills


No one is saying CO isn't dangerous, of course it is, but your version of the threat is outright chicken little fear mongering based on a very shallow understanding of CO sources and the threat it creates on a boat.

BTW, lots of boats carry pure O2 for any number of reasons, medical or otherwise. It is no more a threat to life than ethanol or CO for people who understand the risks and how to manage them.
 
but your version of the threat is outright chicken little fear mongering based on a very shallow understanding of CO sources and the threat it creates on a boat.

Sounds like the fear of a gasoline boat , or having propane aboard,

fear for the sake of fear ,

or perhaps to justify a different decision by the writer.
 
FF said:
but your version of the threat is outright chicken little fear mongering based on a very shallow understanding of CO sources and the threat it creates on a boat.

Sounds like the fear of a gasoline boat , or having propane aboard,

fear for the sake of fear ,

or perhaps to justify a different decision by the writer.
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My limited knowledge of CO has been gleaned from mostly three sources, USCG website, NIOSH website and a long time client who is a professor of haematology.
CO accumulates in the blood and is very slow to dissipate. While diesel does produce less CO than gasoline, If on a 3,4 or 5 day run with a diesel exhaust leak, CO can accumulate in the blood faster than it dissipates and could reach dangerous levels. If you disagree with this , thats fine too, however the professor agrees with me..
 
The threshold limit values (TLV) for CO in underground metal mines in the US are set by MSHA and in Canada by CANMET. Part of my career has involved working in underground mines in both countries with the prime motive power being diesel engines for trucks, loaders and ancillary equipment.

The TLV for CO under MSHA is 50 PPM and CANMET 25 to 50 PPM dependent upon the province. These workplace levels are controlled by ventilation and limiting the time equipment is used in particular mine headings. Using monitoring devices such as a Drager, gaseous levels for not only CO but CO2, NOX etc can quickly be determined.

At these TLVs there is no buildup of CO in the human bloodstream or other known health issues. It is not uncommon that work shifts can be 12 hours. Based upon personal experience CO levels well above 50 PPM can be tolerated for extended periods of time with no side effects. There is a large body of science established for CO in the diesel engine work place and for those interested thousands of papers, government regs and convention papers are available on line.
 
Ski in NC said:
Not a good idea unless the two pipes exit right at the transom. As in genny exh tube inserts ME exhaust tube, but both exit together. If tied in any further up the ME pipe, there will be backpressure trying to force exh/water into genny pipe. No big deal if both are running, but if genny is off it can get filled with water.

Worse yet if sea or loading conditions have exhaust underwater, you could force water into the main.

On all the installs I do, gen gets its pipe, ME get its pipe. Why take the risk. Gennies with water in them paid for the construction of my boat. Anything you can do to minimize that risk is worth it. Unless you want me to build another boat!!
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I think y'all failed to notice the full weight of Ski's post!!!


Back on topic. If you want to talk about CO poisoning, start a new thread!
 
Baker said:
Back on topic. If you want to talk about CO poisoning, start a new thread!
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Actually, CO poisoning and exhaust runs have much in common. Particularly in gasoline powered vessels where too many have died from generator exhaust fumes.

The issue being "artfully" debated here is the danger from diesel exhaust, which is quite low and a different story as compared to gasoline exhaust.

And yes, Ski's comments bear repeating.
 
sunchaser said:
Actually, CO poisoning and exhaust runs have much in common. Particularly in gasoline powered vessels where too many have died from generator exhaust fumes.

The issue being "artfully" debated here is the danger from diesel exhaust, which is quite low and a different story as compared to gasoline exhaust.

And yes, Ski's comments bear repeating.
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Agreed but the initial intent of the post is whether or not the generator can share the same outlet as the main. That in and of itself does not increase CO hazard. Then we started talking about exhaust outlets at the transom...which, in theory, could increase hazard to those hanging out back there.

The point here is....the sharing of one outlet for both generator and main exhaust. Should it be done...why or why not. And that has nothing to do with CO poisoning....unless you somehow think their collocation increases the chances of CO poisoning.

BTW...the larger late model Sea Ray Sedan Bridges use this method of exhaust. And they, like most mass production boats, likely come with a placard stating ABYC compliance.
 
Baker said:
BTW...the larger late model Sea Ray Sedan Bridges use this method of exhaust. And they, like most mass production boats, likely come with a placard stating ABYC compliance.
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Therein lies another point on this thread. ABYC compliance does not necessarily mean best, safest or smartest practice. It just means "good enough" - maybe,
 
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