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Author Topic: Drencher system  (Read 5698 times)

davidsg1a

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Drencher system
« on: November 23, 2011, 08:02:41 pm »

Just did a car deck drencher system test on the ro-ro I work on for the MCA, so heres a couple of pics for those that are interested.

David







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Dave13

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Re: Drencher system
« Reply #1 on: November 23, 2011, 08:16:04 pm »

Hi David
Sorry to be thick but what dose a car dech drencher do??
Dave:)
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Shipmate60

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Re: Drencher system
« Reply #2 on: November 23, 2011, 08:27:41 pm »

Dave,
A Car Deck Drencher system is used to contain a fire on a packed car deck.
It stops the neighbouring vehicles catching fire and spreading the fire.
Was that taken on a Wightlink Ferry?

Bob
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davidsg1a

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Re: Drencher system
« Reply #3 on: November 23, 2011, 08:34:59 pm »

Your on the mark there Bob, it is supposed to put the fire out aswell, it starvs the fire of oxygen.
The picture was taken on the Cal Mac ferry Hebridean Isles.

David
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Shipmate60

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Re: Drencher system
« Reply #4 on: November 23, 2011, 08:47:22 pm »

David,
Just finished a summer relief contract with Wightlink as 2nd Engineer!!!

Bob
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davidsg1a

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Re: Drencher system
« Reply #5 on: November 23, 2011, 08:55:07 pm »

Iv never worked for wightlink, seen them alot in pomy when i was with the rfa, my job isnt as exciting as 2nd gingerbeer im an AB, are you just working the agencies?

David
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Shipmate60

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Re: Drencher system
« Reply #6 on: November 24, 2011, 09:56:17 am »

David,
I took early retirement in October last year from Serco (You must know THEM in the MCA) after 32 yrs at sea, had too much time on my hands so looked for a job.
I couldn't find any part time so took a full time relief contract with Wightlink.
That finished in September this year and am now working part time helping a mate get his paperwork in order in a small but very busy Car Body Shop.

Bob
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Colin Bishop

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Re: Drencher system
« Reply #7 on: November 24, 2011, 05:11:44 pm »

Quote
Your on the mark there Bob, it is supposed to put the fire out as well, it starves the fire of oxygen.

Have you read the MAIB report on the Commodore Clipper fire last year? http://www.maib.gov.uk/cms_resources.cfm?file=/CommodoreClipper_Compiled.pdf

It seems that the drencher system was less effectiive than expected as the goods vehicle trailer roofs diverted the water away from the fire inside. Then they had to keep switching off the system at intervals as debris blocking the drains was causing a water build up on the vehicle deck which was making the ship unstable. This allowed the fire to regain its intensity. It was a very difficult fire to extinguish and eventually the burning trailers had to be dragged out after the ship had been docked.

Colin
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Netleyned

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Re: Drencher system
« Reply #8 on: November 24, 2011, 05:20:13 pm »

A true drencher system is supposed to atomise the water from the sprayheads which effectively starves the fire of oxygen
as opposed to a sprinkler system that sprays water on to the fire

Ned
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Colin Bishop

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Re: Drencher system
« Reply #9 on: November 24, 2011, 05:26:28 pm »

The MAIB report refers to a 'drencher' rather than sprinkler system but it probably wasn't the latest design. The problem was that having to turn it off at regular intervals allowed the fire to flare up again. They didn't get the passengers off for 20 hours after the ship had docked as the normal route off for foot passengers was through the stern door and the only gangway access was into the vehicle deck which was on fire! The only other option was to lower them into lifeboats or winch them off by chopper but that was felt to be a bit extreme as they were reasonably safe up at the front of the vessel and hotel services were still functioning.

Colin
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Netleyned

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Re: Drencher system
« Reply #10 on: November 24, 2011, 05:40:54 pm »

The mind boggles
First floor accomodation ashore has,by law,to have an alternative means of escape
There were issues with the Fleet tenders having only one exit from the below
decks accomodation
A ferry obviously does not need this as the passengers can get into lifeboats or helos
unless the ferry is docked when the only escape is through the vehicle deck  >>:-(

Ned
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Colin Bishop

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Re: Drencher system
« Reply #11 on: November 24, 2011, 06:38:09 pm »

Ned,

Commodore Clipper is basically a freight ferry with limited passenger accommodation. and this incident certainly showed up a vulnerability. Apparently Portsmouth port just happened to have a crane managed gangway intended for use with cruise ships but this could only reach the open part of the weather deck at lower states of the tide. But the weather deck is also the upper vehicle deck and the trailers were parked around six inches apart so if they had got the gangway secured, the passengers would have had to crawl under the trailers to reach it! They did eventually find a rather convoluted route around the trailers but too late to be useful.

In extremis the passengers and crew could have been got off using the lifeboats but it was considered that this was not worth risking as the fire had by then been essentially contained although it still took a long time to get the blazing trailers off as when they opened the stern door (manually!) it caused the fire to blaze up again. The drains on the vehicle deck were blocked with roasted Jersey potatoes which fell out as their packaging burned through. Obviously a case of not checking the Chipping Forecast!  %)

Colin
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Shipmate60

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Re: Drencher system
« Reply #12 on: November 24, 2011, 06:56:22 pm »

The RORO's have several contingencies for a fire on the car decks and escape.
The obvious escapes are the loading ramps at each end so if a fire is in the middle or 1 end the other end is available.
There is also a side loading door if both ends have a problem. Plus the normal evacuation systems on both side of the ferry.
As a last resort the nearest ramp would be lowered and the traffic outboard pushed over the ramp into the sea and the crew in Breathing Apparatus connect a hawser from the anchor winch and drag the dangerous vehicle(s) to the nearest end of the ferry in the open and if possible dump it in the sea.
Fire is taken seriously on board these ferries and during my short time with Wightlink we practiced several scenarios.
There is also provision in the timetable/rosters for weekly training on 1 ferry at a time.
This is all in addition to the standard ship's firefighting gear of foam and breathing apparatus.
Unfortunately the Commodore was not a RORO so this immediately knocks out several of the above.
But surely 20 hours is rather excessive within the confines of Portsmouth Harbour.

Bob
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Colin Bishop

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Re: Drencher system
« Reply #13 on: November 24, 2011, 07:11:07 pm »

Quote
But surely 20 hours is rather excessive within the confines of Portsmouth Harbour.

Yes Bob, that is one of the 'lessons learned!'

Colin
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Bryan Young

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Re: Drencher system
« Reply #14 on: November 24, 2011, 07:34:03 pm »

The LSLs (Sir Tristram etc) didn't have a drenching system as such....certainly not as has been displayed here. They had "Water Walls" as a containment device. A less powerful, but supposedly effective, "heavy duty" sprikler system was deployed between the water walls. The inherent stability of the LSLs together with the capability of getting rid of all the water made "things" a lot easier than appears to be the case with modern ferries. I think. BY.
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davidsg1a

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Re: Drencher system
« Reply #15 on: November 24, 2011, 07:48:15 pm »

As Bryan says modern ferries have the problem of getting rid of water off  the car deck, all the ferries my company have, have got freeing ports all the way down the car deck so there is not a stability problem, the system in pics you'll be supprised does not use that much water.

As Bob says on the boat he worked on they had drills once a week its the same with calmac ferries, most of our boat have got open car decks at the the stern which is ideal for DGs, you can fight the fire from deck level or from the upper deck looking over the car deck.

David
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farrow

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Re: Drencher system
« Reply #16 on: November 26, 2011, 09:38:21 pm »

Red Funnel ferries use a drencher system, plus a mobile firewall nozzle to isolate. But the drencher's only cover each end of the lower car deck, the middle third ( where the mezzanine decks are ) has no drencher system if my memory serves me right apart from the usual firemain with hose baskets etc.
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davidsg1a

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Re: Drencher system
« Reply #17 on: November 28, 2011, 11:04:49 am »

Hey Dodes

Now you mention it, I cant remember what the ships with mez decks have in cal mac, I'll have to check that when I go back.  {:-{
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