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Stellar Daisy

Posted: Wed Apr 12, 2017 6:00 am
by JK
Information is from Splash 24/7 postings from the last week. I distilled several articles. I'm hoping that someone familiar with structural strength and conversions from VLCCs and VLOCs will comment.


On April 3rd, the Steller Daisy sank in the South Atlantic, with only 2 survivors. It took 12 hours for the company to organize a response.

The ship was built in 1993 as a VLCC and converted to a VLOC of 266,000 dwt. It is classed by South Korea and flagged by Marshall Islands.

The company spokesman said the ship was old but operated without problems.
(From the Company POV, it probably did operate without problem. It got to its ports, delivered cargo and costs were manageable. I wonder what the shipside POV was!)
It had deficiencies with water tightness that were addressed in China after being flagged by Port State Control. They sailed for Brazil, loaded 260k tons of iron ore and sailed heading back to China.
The ship had severe water ingress and quickly listed and snapped in two before capsizing.

The South Korean government with be mobilising resources to aid in the SAR.
(A little and too late.)

22 are missing with only empty lifeboats, suits and oil slick showing that the ship existed.

Within 4 days another Polaris 1993 built VLOC has had issues off of South Africa. The Stellar Unicorn rerouted to Cape Town while enroute to China with a load of iron ore. It is still anchored there while a 15 cm crack on the stbd side is repaired.

19 of the company's 32 bulkers are conversions from tankers.

Stellar Cosmo

Posted: Thu Apr 13, 2017 5:23 am
by JK
Another 1992 VLCC converted to VLOC has been found to have a "defect" and will need repairs.

Splash 247 is always an interesting publication to read, the author, Sam Chambers seems to have good sources of information.

Re: Stellar Daisy

Posted: Thu Apr 13, 2017 2:11 pm
by Big Pete
I think the main difference with with a VLCC (Very Large Crude Carrier) is that Crude Oil is a Uniformly Distributed Load of Low Density, whereas Iron Ore is a Concentrated Load of High Density.

It is possible that the ship was an Old single skinned Tanker, that was re purposed when Double Hulls became mandatory, in this case as part of the conversion a Double Bottom should have been installed and this should have increased the Longitudinal strength of the Hull.

Iron ore has a wide range of densities from 2,100 kg/m3 to 5.100 kg/m3 ( according to my on line research) Crude Oil of course has a density of less than 1,000 kg/m3.

Therefore she would have been designed so that a full Cargo of Crude would fill the Tanks Volume wise, and the Centre of Gravity (of the cargo) would be half way up the tank, but, Iron Ore would only fill them to between 20% and 50% by Volume. making the C of G between 10% and 25% of the tank height above the bottom, the Structural Strength and Stability of the Ship would have been calculated for crude. Substituting Iron Ore means the Centre of Gravity of the Cargo is much lower, making the ship too stiff, it would roll like a bastard in bad weather, unless the bottoms of the Tanks were raised considerably, or Ballast Tanks were installed under the Main Deck to raise the C of G, but if these were used it would reduce the Deadweight capacity of the ship.
Because of the difference in Densities of different ores, many purpose built ore carriers have heavily strengthened Tank Tops in ALTERNATE Holds, combined with a lot of additional Longitudinal strengthening, so that they can load the strengthened holds full and leave the unstrengthened ones empty to overcome the stability problems and when they
Iron Ore Carriers offer suffer structural damage because of the heavy weight of Iron Ore dropped into them from a great height in the loading Ports, often at tens of thousands of tons an hour, it can be very difficult to load the cargo evenly, unlike with a Tanker, it may be that the ship has to be moved up and down the jetty, delaying operations, in order to load cargo in a different part of the ship, and a lot of pressure can be put on the ships crew to load the cargo in an unsafe manner. Poorly trained crew often do not understand the importance of CONTINOUSLY monitoring the load condition so that AT ALL TIMES the STABILTY and LONGITUDINAL STRESSES are within Limits, it is NOT OK if the stresses are within limits on arrival in Ballast and again on Departure fully loaded, in between the ship could have Hogged or Sagged badly, causing severe structural damage, leading to the ship breaking up at Sea.
However, many Third World Crew would not enter the intermediate states of load into the Load computer nor would they be assertive enough in dealing with the shore side people managing the loading.

I suspect that any Tanker conversion would have minimal safety margins of Structural Strength when loading when compared to a purpose built Iron Ore Carrier, and may have already suffered from wastage of the steelwork in the areas of the old tanks. This could be aggravated by the excessive loading stresses (Stress Corrosion).

BP
I don't have any personal experience of Ore Carriers so if anyone out there knows more, I won't be upset by any criticism, this is what I have read over the years..

Sank like a rock.

Posted: Sun Apr 16, 2017 3:46 am
by JK
I worked on an OBO for a brief time. I left because I decided that life was too short to be that tired and beat up from the rolling with ore cargoes. This is grim reading.

http://splash247.com/rolling-like-im-in ... lar-daisy/


Excellent reading Big Pete I wonder about the condition of the hatches on the ship as well.

Re: Stellar Daisy

Posted: Mon Apr 17, 2017 1:10 am
by Big Pete
Thanks JK, I did one trip on a Panamax OBO as Chief, only carried grain (from NOLA), HFO and Liquid Natural Gas Concentrate, nothing as dense as iron ore. Many years ago I was 2nd on a3,000 DWT mini Bulker, and took the last cargo of lead ore out of the mine in Galway, Ireland, Rolled that a bastard then and discussed putting in the upper wing balast tanks, as we weren't loaded to Deadweight..
Hatches are a good point JK, a lot of people don't realise that the hatch covers form part of the Longitudinal strength of the ship, but ONLY when they are properly cleated down, I have sailed on several ships where the hatches were only properly cleated down when the ship was loaded and expecting bad weather, too many Deck Officers don't understand how much the ship is structurally weakened from its Design State by only pulling down alternate cleats, or one in three...
Down to lack of understanding, and the natural Human desire to find "an easier way".

BP

Re: Stellar Daisy

Posted: Mon Apr 17, 2017 2:19 am
by JK
If the ship had a history of cracking at a hatch combings, or a specific area it would point to the hull working. If bad welding practices were happening with hard points, the problem would be worsened.
The ship I was on was 28,0000 DWT. It carried lead and iron ore, and coal.
It was truly amazing to watch her flex in a sea.

Re: Stellar Daisy

Posted: Mon Apr 17, 2017 7:24 am
by Merlyn
Odes of the Derbyshire back along.

Re: Stellar Daisy

Posted: Mon Apr 17, 2017 10:51 am
by Big Pete
The Derbyshire Class had lots of faults, nearly all the experienced Welders had left the shipyards to build Natural Gas pipelines, they were welded by half trained welders on piece rates who filled the gaps between the plates with bundles of welding rods and then flashed over the top, there were structural discontinuities where the Longitudinals through the tanks didn't line up with the ones through the Machinery Spaces due to shoddy Draughtsmanship, lack of supervision by the Yard, owners and Class allowed them to built that way.
Lot of problems with them all Kowloon Bridge et al.

BP

Re: Stellar Daisy

Posted: Mon Apr 17, 2017 12:50 pm
by JK
Wasn't the official finding that it was an open man hatch that caused the Derbyshire sinking? I guess they retroactively couldn't change the investigation results. The open hatch flooded the forward space, the bow dropped and the force of the waves were on #1 hatch which failed. Now a days the #1&2 hatches are required to be strengthened.

The OBO used to work enough to pop man hatches open. We'd heave to and they'd scurry forward to close it and we'd scurry about in the spaces while the ship was relatively still to check that things were still lashed tight.

The breaking up of the Kurdistan in the Gulf of St Lawrence was a bad weld on a bilge keel. The ship was Grade A steel, they had a heated cargo and went into the ice. They couldn't make any headway, so moved out into open water where the ship broke in two. That changed the rules on notchproof steel for ice.

Re: Stellar Daisy

Posted: Tue Apr 18, 2017 12:15 am
by Big Pete
I don't know what ship it was but I remember reading about a ship tht was extensively built using High Tensile Steel, and damaged her Bilge Keels, they were repaired in a small out of the way place that had no knowledge of High Tensile steels, as a result the entire Bilge keel tore off the Hull, leaving a a long hole in it..
All very scary stuff, for innocent sailors.

Re the Derbyshire I remember seeing pictures of the wreck, taken by ROVs. The showed the Fo'c'sle hatch open and the mooring ropes trailing out through it. I always wonder if one departure from the previous Port the crew had failed to stow the ropes properly and had left the eyes on Deck and just dropped the hatch on them to save work when they next arrived in Port. I have seen that done many times, " The weather is Good, we have lots of Free board no Problem"", then the Typhoon hits and nobody wants to go forward, drop the ropes into the Fo'c'sle and Dog the hatch down properly.
The Hatch was also badly designed, the Hinges were at the aft end, so that a wave impact could lift the hatch. I could see a scenario that if the hatch was dropped on the ends of the mooring lines, and then dogged down, the impact of waves on the hatch would push it down, taking the load of the dogs and allowing them to fall free, and then lifting the hatch, and throwing it right back.

One of her sisters broke up on the Irish Coast and when the wreck was inspected they found that the Longitudinal frames weren't continuous. The entire Class had a history of repeated transverse cracking in way of the pump room Bulkhead. I think it was the Deckhead Longitudinals aft of the Bulkhead were about half a metre out of line with the ones forward of it. British shipbuilding was Nationalised at the time, and Class and the owners hadn't noticed anything wrong, nor sadly had the crew. Lot of pressure to keep things quite.

The Families of the crew of the Derbyshire formed a powerful and effective pressure group and heavily publicised the faults of the Builders, Class and the Owners, but were understandably more reticent on the shortcomings of the crew....
However, the owners are always responsible for ensuring that their crew are competent and able to operate the ship safely, and that they actually do so.....

BP.

Re: Stellar Daisy

Posted: Tue Apr 18, 2017 11:54 am
by JK

Re: Stellar Daisy

Posted: Wed Apr 19, 2017 5:11 am
by Merlyn
Just reread all the official reports of the sinking, pretty horrific loss all round.
Apparently ingress of water through two deck hatches not secured properly filled up the forward hold when then popped the hatch cover.
Further ingress of water then popped the second one and so on and so on back to the bridge.
Really roughers jobby, thoughts spring to mind re 180 turn to prevent/ cut down / out further water ingress i.e. Downwind steaming together with bilge pump alarms/ float switches etc etc. Getting rid of it over the side didn't happen.
Seems they never noticed the bow down angle until it was too late.
Seems at the end of it all crossmember 65 let go as it did with her sister ship but like BP said re the correctly secured hatch covers being an integral constuction feature popping all the hatch covers one by one and viewing it from the bridge must have been pretty horrific to say the least.
Must have been flexing plenty with all hatch covers gone under those weather conditions.
Bow must have been well submerged on her final dive.
She broke up into over 2000 pieces when found some fourteen years later.
Horrific way to go.
No distress calls whatsoever transmitted.
Final findings stated frame 65 only let go on the way down as the stern section was found 600 feet from the bow section.

Re: Stellar Daisy

Posted: Wed Apr 19, 2017 11:05 am
by JK
I saw the video of the sinking of the Gold Bond Conveyor that was taken from a SAR Aurora plane. The ship sailed into a wave and never came out. It was horrific.
it is described here:
http://ngc-heritage.com/op-ships-colonbrown.htm

Merlyn, what I have read is that when the first cargo hold is breached, the bow goes down, the second hatch is breached and the ship goes down so fast that the hull implodes.

The bulker trade had a lot of caualties in the 80s &90s but losses were lower until the liquidation of cargoes and subsequent founderings that have happened.
IACs is concerned over the loss of this ship as it could be indicative of inherent issues in the conversions.

Re: Stellar Daisy

Posted: Sat Apr 22, 2017 12:24 pm
by Big Pete
One of the main lessons of the Derbyshire loss was the requirement to fit flooding alarms in places like the focsle, pump room and cargo holds, and large Buoyancy spaces (Void spaces), previously only the Engine Room had Bilge alarms.
Way back before manpower cuts, the Mate would have sent one of the crew or a Cadet, round to manually sound all the Holds, void spaces, Ballast and Fresh water spaces at least once a day, many standard log books have a printed column for these readings for every WATCH i.e. they were expected to be taken every 4 hours, no chance nowadays, when you need Dynamite to rise any Officer from their Computer.
BP

Re: Stellar Daisy

Posted: Sat Apr 22, 2017 8:11 pm
by JollyJack
Wasn't that the Chippy's job BP? Not every ship had a cadet, but every ship had a Chippy.

But where are the Chippies, Chief Stewards and Leckies
Where are the Sparkies and 6th Engineers?
We've gone "micro manning", they're all disappearing
Fading away in the mists of the years.

Doesn't apply to Government vessels, of course, they still need huge crews to justify sparkly gold braid on senior office types. :)