My experience at MSC with cargo hold vents

It’s been expressed here what a horrible sin it is not to have cargo vents in good working condition.

I was on a RO/RO, the Mercury, my second ship as third mate after sailing about 10 years unlicensed and as C/M mate on coastwise tugs and the Aleutian freighters. One of my jobs was to inspection the louvres/fire dampers in the cargo hold vents. To get at them you had to get a ladder up inside the vent covers.

The very first time I checked them I found they couldn’t be budged. I tried oiling them up, banging on them but no luck. So I went to ask the C/M what to do? Well the C/M barely acknowledges my presence, I just get a grunt from him. Up until then I had been very impressed with the C/M’s knowledge of the ship etc.

So check to see what the previous 3/M was doing. The reports that the previous third had turned in each month all said the same thing, “all vent in the open position”. So I dig back further, what was the guy before doing? Same thing, “all vents are in the open position”.

Well, this ship uses fixed CO two for firefighting, how’s this going to work? So I filled out the inspection form “ventilators are all stuck open” with a note - I can’t get them closed. I turn that over to the C/M with a note saying what I’ve found.

So about a week goes by, no word from the C/M, no action on deck and the C/M is giving me the cold sholder. So I might have been a little naive about how politics can work on some deep-sea ships but I left a note on the captain’s door, that the vents couldn’t be closed.

The next day, the entire deck department is out working on the vents. But that C/M, from then on, as hard as I worked on there, did nothing but try to make my life miserable.

Point being I’ve seen a fucked up shit on ships where it’s all been signed off as OK. When ever I hear someone talking about how they did things properly when they were third mate I take it with a grain of salt. There are more then a few mariners out there not doing what that they say they are doing.


When I sailed as third mate, the first week I was onboard I’d go through both lifeboats and count everything to get my own baseline. Usually found at least one thing expired / missing that had been dutifully checked off by the last guy.

As second mate I’d thoroughly check the charts and pubs on my first week. Most of the time things were good, but then other times, shit was all fucked up.

As Chief mate I would sound the ballast tanks within 24 hours of joining. I sailed opposite an excellent counterpart but always wanted the piece of mind and check against the gauges that may have failed while I was home.

Now as master I take time to check every personnel file in the first week to make sure I’m not going to get blind sided in a port state or audit for someone I didn’t sign on.

Most of these quirks and ticks (and several others I haven’t mentioned) have saved my ass a few times over the years. What bothered me the most all those years and still does is what you described. Someone recognizing a problem, reporting it and the person in charge of getting it fixed ignoring it. Politics aside, if you were my third mate I’d have given you an atta boy and that Chief mate a frank discussion on his shortcomings. Good people need to know they’re appreciated and ones who half ass things need to be shown the door.


ya, even synthetic bushings don’t help much on those louvers, and underway they don’t get exercised, I’d just guess most deep sea ships have plenty of stuck ones but at least ours got working at inspection … pity!

The obvious answer to me would be to exercise them weekly or monthly, perhaps as part of a firefighting-readiness drill.


when at sea over a month or so a lot of salt gets hauled in there. further, closing (exercising) the vents underway with ventilation running , the vents get sucked shut and often won’t open again until ventilation shut down, enuff krap happens on watch without having to climb up the fidley. when you get to port they’re frozen open again! CO2 is heavier than air, I’ve wondered how much would really escape thru the top with the fans off.

1 Like

Yes to this. Salt and grease make an almost cement like substance that typically requires diesel to cut and remove.

Yes, there was a requirement to do them once a month. The last two third mates (or more) didn’t do them so they were stuck. Once they got busted loose doing them after that wasn’t a problem.

These are RO/RO cargo vents, they were normally only run during cargo ops for exhaust fumes. The vent are up inside a housing, so they are not exposed direct to the weather. As long as they get exercised once a month there’s not a problem, or at least an easy fix,

As far as not closing them in a fire, maybe the CO two would stay inside with no fire but with any kind of fire there is going to be a of mixing and convection, need to be closed.

You can see what looks like boxes running along the deck near the side, those are the cargo vent houses.

RO/ROs cargo holds need a lot of ventilation during cargo ops.

1 Like

My first C/M job one captain kept harping about “not falling behind on the vents” and I was able to get very little else done while he was aboard, his relief didn’t much care about the vents but busted my chops hard about “doing nothing” while he was off. In truth I sided heavily with the latter until, a few months into the job we had our first fire - It was a fairly large fire in a CO2 protected space - and I quickly switched sides.

The problem with vents is they really suck up time and energy… and its hard to justify that time to those who have never experienced a fire or flooding.

1 Like

Yes, it seem always to be the case that there are other tasks more urgent. Imagine if there had been a fire with the vents all stuck open. People would be in disbelief that such a thing would be allowed to happen.


TOI was busted multiple times for the state of the vents/fire dampers on many of their ships/semi’s and have had a few of their ships go on down time until ALL vents were 100% - we heard a story about a ship where, during a USCG inspection, was asked to function a few theirs…one inspector was going to be on the bridge at the panel an one locally at the vent…the C/M actually sent an AB with the inspector to the vent with a rubber mallet to make sure he could beat the vent shut if he had to…with the inspector witnessing. Unfortunately, HVAC systems in general and fire dampers/vents in particular seem to be given the least amount of attention while in the design phase. I’ve always had the policy that no matter where you are, who you are with, etc, that vents thrive on attention and need a bit of Kryoil sprayed on their moving parts ever single time you look cross eyed at them, which keeps you out of trouble and from having to spend a lot of time of them…because no matter what you do, especially if you DON’T give them a lot of attention, you are going to spend a lot of time and money eventually anyway.

1 Like

While I agree 100%, it’s not just a problem at TOI, it’s a problem on most large MODU’s because of the shear amount of workspaces within the hull that need to be ventilated and the fact that, while most ships are venting out mostly dead air, MODU’S are frequently venting barite, bentonite, off-gassing mud, etc. The high humidity in places like the gulf doesn’t help either nor does the low lattitude ssun on any rubbertopside topside.

And, you’re right, naval architects and shipyards cut corners because upgrading the ventelation system on the dozens of separa systems aboard a MODU would cost tens of millions of $. In fact most of the mechanical problems we dealt with on the maiden voyage of one $750 million drillship I helped deliver where with vents and dampers.

Ugh, man, it took us a good year to get the dampers freed up on a drill ship what was one year old before we got to her. And you are spot on - the spaces that are ventilated on those things just carry all kinds of stuff that seem specifically designed to seize them all up. BUT - they thrive on attention and if you give it to them on a regular basis, even a bunch of ignorant rig hands can keep them 100% with out spending a bunch of $$$$ and, eventually, time.


That actually happened on a drill ship where I used to work - fire in the engine room and they had to go through the stack to beat the dang dampers shut before they pulled the CO2 system. Or so the urban legend goes…

1 Like