Damage Control Question

Professional Mariner Forum
1

Question for you guys

If you happen to have an explosion, not a huge one, that results in a fire and busts your firemain local to the fire, what do you do?

a) isolate the leak and haul firehoses from wherever possible

b) keep your fire pumps on, fight with the closest available on, and deal with the 2,000gpm+ when the fire is out

c) wave good-bye and head for the life rafts

How does the answer change with the location, e.g in the middle of the deck house, down in a pump room or aux machinery space, or a space that drains overboard?

I more or less know the Navy answer, but even there the answer is convoluted depending on the size of the leak and the amount of coverage lost when it’s isolated.

Thanks for your help.

2

The answer is “A”. There are shutoff valves in the firemain loop that allow one to isolate portions of the piping if a section is damaged.

3

Based on your apparent background, which I take is Navy, your question presumably has to do with larger ships (+300 LOA).

My comments below probably won’t pertain to you, but here goes:

For vessels smaller than 300 feet LOA “A” is one answer, but on smaller vessels you may not find isolation valves in the fireman.

Some vessels will have EDFP (emergency diesel fire pumps). These are portable, and draw water from the sea. At the company I work at, during annual ff training, setting up the EDFP early on in a fire, even if not needed it, is SOP, so that if fire main pressure suddenly drops, you’re set.

My personal observation when it comes to the free-surface/weight of water issue is: a) yes, it can be a problem, and b) don’t worry about it in an initial attack. For belowdecks ff, using water to extinguish the fire is initially a matter of generating steam to reduce the O2 level in the compartment to <15%, to knock down the flames. This takes comparatively little water. Then, solid water is used to break Class-A ember materials up, but this should be a targeted matter, not spraying water willy-nilly.

You mention 2000 GPM. Using that flow continuously for 30 minutes means introducing 258 short tons of water into the ship. But a half hour of fire fighting time is a lot of time. 258 tons, even if introduced into the upper decks of a comparatively small ship may not compromise stability, and on the weather decks, of course, means nothing at all.

Water application in compartments is an arcane subject. Go to different marine ff schools and you may get different answers.From listening to experts, and by running a realistic ff simulator, I suggest this: whenever possible in a direct attack on a big, hot fire down below, put a bulkhead between you and the fire. Shoot the water through the doorway into the overhead. Rapidly target several spots in that overhead. Then close the door quick. If things go right, the water will flash to steam, expand and reduce the O2 level to below 15%. Flames out. (Caution: if you are foolish and leave the door open, the steam will reach out and scald you.) Wait a few minutes. Then repeat.

With vessels with large amount of Class-A materials aboard there is more to it than that.

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4

Thanks it does help.

I was in the Navy & assess primarily Navy designs; a commercial one has come across my desk.

The design has a LOA of 300’+ (>500’), but there aren’t many isolation valves. About a half dozen more on the ship would make life a lot better.

The mechanics of putting out the fire isn’t the issue I have; it’s that an isolation valve has to be cycled to support using a local-ish hose. The choice is haul a hose from 300’ forward & up 4 decks or use one from a deck or two below while having a water fountain above.

Is it realistic to suggest they would cycle the isolation valves to support using a local hose? Or just use the local hose and deal with the water fountain later?

I’ve seen some, um, innovative (i.e. goofy) approaches to DC in design reviews over the years. I’d rather not provide someone a belly laugh if I can avoid it.

5

Do what you think is right. If somebody laughs because you are trying to be safe, screw them, and remind them again when their ignorance costs a few million or a few lives but never say “I told you so.”

Insinuate that when you are rubbing their nose in it…

6

Sorry BMCS, I’ve seen some really silly stuff proposed by some of my peers. Some of it defies the laws of physics and shouldn’t have gone beyond their desk.

Commercial ops are a bit foreign to me. If my thinking goes beyond “out of the box”, I’d like to know before I put it down on paper and make an ass of myself.

7

I don’t know what type of vessel you’re talking about but consider the crew size too. In certain circumstances it’s just not feasible to fight certain fires without endangering crew lives. A direct attack with a bunch of 20 year old navy sailors who drill regularly on this with the expectation that they should be able to perform in combat is one thing, 12 out of shape mariners are going to be a limiting factor.

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8

All the ships I have been on (at least the last 30+ years) had fire control plans posted as well as rolled up in tubes. Those plans show the layout of the firemain, its valving and stations. If there is a break in the line, a look at the plan will show if it can be isolated and other stations in the system. If the line break is bad enough it will prevent effective use of any hose station due to line pressure loss.

Maybe I am the odd one here but I knew where the isolation valves on the firemain (on my old ship) and wrote a PM to periodically exercise them to make sure they worked.

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9

It’s your canoe. I have been doing this long enough I normally go with my gut. Sometimes you can’t explain things to everyone’s satisfaction but you know it is right.

Now, making an ass out of myself? I am well past the stage of worrying what other people think. I have over 40 years experience doing that AND have a doctorate in it. Ask anyone that knows me…

Good luck to you!