Generators and carbon monoxide

This summer we plan on taking trip along the Gulf Coast from New Orleans to Pensacola anchoring overnight in several locations. Hot evenings require the use of the genny to keep ACs running. I always have this fear of running that genny while we sleep. Any slight leak of exhaust inside the boat could be deadly. My children and grandchildren will be with us on this trip. I have been on countless trips running that genny all night with very little concern but having my entire family on board I become super cautious.
What type of sensor/monitor do you guys use on board for CO/CO2 alarm? Also exactly what do I need to check on the genny for any forms of exhaust leaks. Should I place a monitor in the engine room next to the gen? Am I being too paranoid?
Any help on this area would be appreciated....thanks.

When you get a CO alarm, it is very important to use high quality batteries; otherwise you may get false alarms. Mine is located in the salon.

We have kidde home type smoke and CO alarms, tied to our alarm system.

That said, if you have a diesel generator your risk of CO poisioning goes to zero.

The very best CO detector for a boat is one designed for a boat. They are considerably more expensive than residential CO detectors but if you're going to run a genset while sleeping and a gasoline powered genset in particular, they would be worth the extra cost.


I have a diesel powered boat and no genset and a CO detector is not required but I installed one anyway. It's possible for exhaust and CO to migrate from a nearby or rafted boat into mine.


If you are really concerned about the genset, have a well qualified mechanic check it out. Tell him your concerns.

One in each stateroom. Any good one from a hardware store will "do". In our case we had the fancy Fireboy-Xintex type that ran off the boat battery banks.
Marine Carbon Monoxide Detectors | Fireboy-Xintex

Assuming a diesel generator in decent repair, yes, you are over-worrying a bit, but nonetheless CO detectors are a must in my opinion. Surprised it wasn't a survey item.

caltexflanc said:

One in each stateroom. Any good one from a hardware store will "do". In our case we had the fancy Fireboy-Xintex type that ran off the boat battery banks.
Marine Carbon Monoxide Detectors | Fireboy-Xintex

Assuming a diesel generator in decent repair, yes, you are over-worrying a bit, but nonetheless CO detectors are a must in my opinion. Surprised it wasn't a survey item.

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We have two of that same CO detector on our new boat. There is one in the main saloon and one in the master stateroom. We don't have one in the guest cabin. I just replaced both of mine as they hit their 5 year life span and became non-functional. I believe I found them online for just under $100 each. If you are going to have a CO detector, I think that it is worth getting one that connects to the boats electrical system instead of using a replaceable battery. OTOH, a battery powered CO detector is simple and easy to install so can be done in a few minutes. Take your choice.

I think that it is appropriate to be cognizant of the risks of CO poisoning. An exhaust leak could be a problem. OTOH, keep in mind that your genset air intake is also sucking air out of the engine room and that air gets ejected with the exhaust. So the leak would need to be pretty significant to be greater than the air exchange from the air intake (that make any sense?). I don't think that you have to worry too much but the other option for increased piece of mind would be to run your ER blower during the nights that the genset is running.

ksanders said:

We have kidde home type smoke and CO alarms, tied to our alarm system.

That said, if you have a diesel generator your risk of CO poisioning goes to zero.

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I do have an Onan 8kw diesel. Are you saying that diesel exhaust has no poisonous gases to worry about?
Last time on the boat I had a sweet exhaust smell in the cabin when I ran the genny for over a couple of hours....just concerned.

As mentioned, CO from diesel is typically not a health issue, but what WesK says below is very true.

Several years ago here in South Florida a couple died on their boat from CO from a neighboring vessel's gas generator.

WesK said:

It's possible for exhaust and CO to migrate from a nearby or rafted boat into mine.

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As Kevin and others noted above, a diesel engine produces very little CO. I suspect that you could breath the exhaust directly from a diesel and it wouldn't cause CO poisoning. Other stuff maybe, but not CO.


The concerns about CO poisoning from generators on boats, come from gasoline powered generators, not diesels.


David

Our CO detectors are Saf-T-Alert systems from MTI Industries, one in the saloon and one in each stateroom. MTI has "Marine" and "RV" models, but their tech told me the two are the same except for labeling... and the RV models are more commonly available and at lower prices from easy places like Amazon.

Our runs from the boat's DC systems.


FWIW, I've read CO detectors have a finite lifespan, often 5 years from the time they were first energized. Something about the life of the sensor inside...

-Chris

From a small diesel generator the CO emissions are very low, but cumulative, as CO works its way out of the bloodstream slowly. If you were exposed to diesel CO emissions for several days you might begin to feel the effects.

EPA estimates CO from a gas auto engine to be over 6 times as much as a small diesel truck.

A well maintained diesel generator with a well designed exhaust system should pose no significant health risks. The risk from nearby vessels still applies. CO Detectors are always a good idea.

ragin cajun said:

I do have an Onan 8kw diesel. Are you saying that diesel exhaust has no poisonous gases to worry about?
Last time on the boat I had a sweet exhaust smell in the cabin when I ran the genny for over a couple of hours....just concerned.

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Thanks for all the great responses! I do have home cheapo fire/co alarms in salon/cabins. Read that these units do not monitor that well in boats. Gonna check the exhaust system really well and change over to the Fireboy system. Worth it for peace of mind!

Where does the notion that home detectors are "lesser" sensors than marine ones?

Anyone have side by side tech data to verify that?

Other than power source....differences?

ragin cajun said:

I do have an Onan 8kw diesel. Are you saying that diesel exhaust has no poisonous gases to worry about?
Last time on the boat I had a sweet exhaust smell in the cabin when I ran the genny for over a couple of hours....just concerned.

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Here's a TF prior post w/ some interesting / related links

I still have not seen any credible reports of death due to diesel marine main engines or gennies - gas yes - neighboring gas yes - diesle NO

I have a diesel genset and the boat came with this puppy hard wired in.

I have a Smoke/CO a Kidde I believe, from Lowes in the saloon. I plan to get a fire alarm for the cabinet where the electric panels are.

Even in the southeast during the summer, the temps normally drop into the mid 70's at night. Your AC shouldn't be running that much over night and if it is just two of you, you only need to cool the master stateroom over night. Perhaps you should be looking at a load analysis and consider adding batteries instead of running the genny over night. The idea is to run the genny to top off the batteries and then turn it off when you go to bed and the batteries should keep the AC running overnight if the house bank is sized properly. Most folks don't like the noise from the genny overnight anyway.

But the carbon monoxide alarm is still a good thing to have.

ranger42c said:

......... FWIW, I've read CO detectors have a finite lifespan, often 5 years from the time they were first energized. Something about the life of the sensor inside...

-Chris

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That is correct and many of the residential models now come with a permanently installed, non-replaceable battery that lasts as long as the sensor.

psneeld said:

Where does the notion that home detectors are "lesser" sensors than marine ones?

Anyone have side by side tech data to verify that?

Other than power source....differences?

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They are designed to meet different standards. I don't know how they are different but I'll bet it's on the Internet somewhere.

These things don't just sniff CO and go into alarm like smoke detectors do. They measure the level of CO over a period of time and then alarm if necessary.

Keysdisease said:

As mentioned, CO from diesel is typically not a health issue, but what WesK says below is very true.

Several years ago here in South Florida a couple died on their boat from CO from a neighboring vessel's gas generator.

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Shortly after we got our boat, we were invited on a group cruise. We were to anchor the first night, then continue on to a marina the next day. The very first thing the guy next to me did once he tied up to me was fire up his genset. The exhaust was about a foot from my hull.

Fortunately, the anchor drug and we eventually spread out and anchored individually.

I use a domestic CO monitor. It beeps when batts get low, and once about 5yr old it kept beeping with good batts, apparently sensor pooped. So I replaced it.

I can't see a big difference between marine and domestic. Houses have furnaces, stoves, cars in garages, barbeques, etc... Lots of potential sources. Risk similar to that of boats.

Diesels don't make much CO, but do make some. They can make a good bit if overloaded and making black smoke, but that is rare for marine gennies. If you see black smoke, back off the load.

On my ride, even in the summer if I run the AC hard for a couple hours before bed, I can shut it down and boat stays comfortable til sunrise. I have run it all night, but not often. Inverter runs the fridge overnight.

I've been the engr on a boat gennie CO fatality investigation. That was sobering. Gasoline gennie, mixture set too rich and it made LOTS of CO. Came in under sliding glass door. Engine room blower left on drew a slight vacuum on whole boat interior.

psneeld said:

Where does the notion that home detectors are "lesser" sensors than marine ones?

Anyone have side by side tech data to verify that?

Other than power source....differences?

Click to expand...

I don't think I've ever seen a statement about the residential sensors not being "good enough" to detect CO. I have read -- but this is only third-, fourth-, or fifth-hand info at best -- that certain household sensors might be more prone to false alarms in a mobile (RV or marine) environment.

Note "certain" and "might" -- with no more definitive info usually available in those kinds of statements.

Even if true, don't know if that would condemn all residential units... and anyway I'd guess it's likely that some protection is better than none, so folks can buy whatever suits their budget.

-Chris

Just installed a diesel heater. Was told we shouldent be without a CO detector. We already had 2, salon and stateroom, just precautionary. Curious if there is a greater CO risk from a heater (different combustion parameters?) than a diesel engine thus increasing potential risk of toxicity?

I disbelieve there is any difference in terms of safety...

Usually requirements are the same and guts are the same.

I will continue to use and recommend household ones until proven to me otherwise as the respond to well below the threshold of remote danger.

My experience with marine ones from a years back was they were very unreliable from false alarms to no alarm at all. The new ones might be better....but I have no reason to change my mind or recommendation....but certainly will with the tiniest shred of proof that certain ones are better than others.

I'm curious as to how you think the exhaust from the Gen would get into the boat if you have the A/C on?

Why are you not concerned about the engine exhaust?

Also, do you think you would not smell the exhaust?

Actually, bigger risk of engine exhaust getting in, but then, that involves physics, which is usually absent on most of these conversations.

The marine versions should have some conformal coating on the innards to mitigate corrosion, that and the ability to hook up directly to a DC source instead of relying on also-corrosion-prone AA cells would be the advantages.

We sometimes take one statement and turn it into another. Here, we're stating that we're not aware of a boater dying from a diesel generator. However, we also stated that the exhaust was not harmful. That part is not true. It's just that the harm would probably be very slow in coming and combine with other exposures during your life.

I want to mention that generators aside, any boat with a propane galley stove definitely needs CO detectors because unvented gas stoves give off quite a bit of CO. Last year when our oven was accidentally left on during a cold day with Windows all closed, the CO detector went off due to the buildup under those circumstances.

Ken

One other little tidbit to be aware of.

I was once told that once you get CO into your blood stream it does not leave you after a period. You get to keep it. So multiple exposures over time can cause some real issues. Not sure of the validity of that.

Here is a clearly written article.

CO Health Risks - Detect Carbon Monoxide

Diesel exhaust has a lower percentage of CO than a gasoline engine exhaust. Diesels ingest much more air per unit of diesel burned than gasoline engines. Spent many years in the underground mining business where diesels proliferate and what would run us out of a heading first was heat rather than a CO buildup. Never seen a gas engine used UG.

But, if any concerns inside your vessel get a Drager air quality tester. They are simple and foolproof.

Several deaths with gas generators at Lake Powell over the years. Tragically people like to swim beneath the houseboat pontoons with the gensets on. Another died from barbecue exhaust fumes trapped beneath/between the hulls.