Being gassed as you sleep at night in your cabin

Last night I was a passenger on an overnight ferry. Woke up in the small hours with an acrid smell coming out the aircon unit. Had a very sore throat and now my chest feels tight.

Can someone suggest a possible cause?

We were told a fan belt had failed… But I have never come across a fan belt inside the air ducts of a ventilation system. The smell was not rubber but oily. The smell I got from the ships staff was distinctly similar to manure :fearful:

There are or can be belts in Air Handling Units (AHU) and burning rubber can be a pretty obnoxious odor if goes on for a long time. Depending on how new the system is there could be alarms that would alert an engineer to such situations by monitoring the AHU static pressure.

An AHU with belt driven fan inside could account for such a smell. Other places to look would be where the fresh air inlet is and any work or other odor generation going on in that vicinity.

Finally if you cabin was equipped with a reheater and hadn’t been called on to re-heat the delivery air in a long time it could be burning off accumulated dust/dirt/grime. This would affect your cabin but not the whole zone - unless the same process was going on at the AHU with the pre-heater.

Not sure why the crew would make up a story about belts, the explanation may be less fishy than you think.


That doesn’t make sense. A fan belt connects the motor to the pulley that drives the fan. For what you describe, both the motor and fan would be inside the air circulating duct. where they wold be difficult to service being inside the ducting. That would be a very seriously dangerous design as it would allow any combustion products from a potential electrical fire in a motor to be instantly fed to sleeping passengers in their cabins.

Sorry to tell you tomahawk but KPChief is telling you the truth. From my experiences, the vast majority of HVAC airhandler units have the electric motor connected to a squirrel cage type blower via a belt inside the air ducting. In many cases these air handlers come in a prefab unit ready to connect to the air return/discharge, power & to the gas lines. The top picture from the wiki page link attached is a good example & gives a visual explanation of the usual set up.


KP Chief is steering you straight. I’ve had the entire house of the ship fill with burning rubber smoke when a belt burned up. Not a pleasant smell but distinctly rubber like.


The airhandlers should be routinely opened to adjust & inspect the belts. Filters need to be inspected, cleaned or changed. The bearings will also need to be periodically greased as well. If the person doing the maintenance lets one rip with the airhandler open, it will result in everyone being gassed. Oddly enough, I have meet several people who gained a lot of satisfaction by farting in the airhandlers. I have done it accidentally when doing long jobs like changing motors or squirrel cages & it always made me smile. Maybe you were gassed, how long did the smell last?

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Horrified at such a poor design!
It’s one thing to have an AHU serving a building where people are awake. But in the confines of a small ships cabin with no outside ventilation is another. If electrical components that can catch fire are inside the air systems so that smoke and combustion products are pumped into sleeping accommodation it is only a matter of time before someone is killed.

Yes that is terrible. The ferry should be better regulated by the state that it travels in. You should demand further regulations be issued that insures the ferry has enough mechanics hired so no one suffers as you have. Of course the ferry ticket price may go up to cover the over head but that is better than smelling a burning belt or having some products of combustion pumped into a sleeping compartment. We wish you luck as your efforts may result in more mariners being hired and you traveling safer.

When I took a cruise our staterooms had individual minisplit units, not the central unit. The same for large modern construction vessels & newer AHTS’s, everyone controlled their own room with a minisplit or FCU (fan cool unit). I guess before the technology was readily available people didn’t care & just roughed through it as we did without so many other modern conveniences that we now find essential?

If it wasn’t rubber but oily, how do you know it wasn’t a refrigerant leak? Many refrigerants have an “oily smell.”

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Around ‘72 or so I was on a 165’ seismic boat with about 35 on board. About 0500, the BR guy mixed bleach and ammonia in the swab bucket. He set the bucket down next to the air handler intake and started his days work. Didn’t take long to get everyone’s attention. We had 2 asmatics on board that really got hit hard.


Thanks to all for the useful input.

I have written to the company… No reply in 24 hours.

The MCA have also been notified. They have referred it to the local office at Dover…

Rest assured, AHU’s are used in buildings where people sleep such as apartments and hotels. Heck, they use them in hospitals too. Hopefully your ship’s cabin didn’t have any other source of potential electrical fires that could spring up in your sleep, such as lights or outlets.

I am not sure if it made it to the CFRs, but ABYC has been “requiring” CO detectors in sleeping cabins for some time now.
Require is in quotes because ABYC does not make actual laws, but boat manufacturers generally follow their rules to avoid being sued if for no other reason.

Sounds like a touch a that Wuhan…better get yourself down to the local quarantine ASAP.

The only time I got “gassed” was when doubled-up in crew’s quarters!!
I’d go for stinky rubber anytime after that.

24 whole hours with no reply? Wow. Don’t they understand how important you are? Maybe go visit their offices in person and do a Rumpelstiltskin meltdown in their lobby. That should get some results.
Here’s the thing … I have got to believe the vessel that you were on was inspected and classed. Meaning that plenty of people (probably a lot more savvy about these kinds of things) have reviewed, and approved, that HVAC arrangement. Something to think about while you are waiting for someone to get back to you.

One tug in our fleet had a strange problem with guys getting sick. After looking everywhere the Chief pulled to filter (Filter was not that old or dirty) out of the Air handler and took a look inside. He found a baking pan almost full of bleach hidden inside. Turns out that one of the crew had mentioned being allergic to the smelt of bleach, they never caught the Asshole that did it but we all kept a close watch on out air handlers for a while.

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I worked on a cruise vessel and every room had a unit in the overhead with a chill water coil and heat strips. They can stink in the beginning of the season.

I work on air handlers with belt driven fans all the time. They have them on most of our fleet. It’s plausible that you got a whiff of burning belt which can be very acrid and irritating.

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