Ferry Stripdown: Drydock of PRIDE OF BRUGES: TV Documentary....

[Captain Kong]

My worst near miss on a tanker, was when the Valve spindle sheered off at the bottom of the tank, there was still petrol in the tank as we were draining and was full of gas, I went down with a BA Set and a large stiltsen, I fixed the valve but the 20 minute tank had expired in 10 minutes, because of the extra effort and had run out as I was climbing up the ladder,
I was sucking on a vacuum. and barely made it, the man on top heaving me over the coaming and I collapsed on deck.
I then invented a plastic cylinder, open at the bottom with a compressed air hose radiating around the top inside. like a diving bell. With an earth wire for the static electricity, if a man was caught at the bottom he could crawl inside and get fresh air until the men on Deck could come down with a spare bottle. It worked.
Cheers
Brian.

[Louis the Amigo]

Hi shipmates how many of you cement washed water tanks? I understand some dont like to do any jobs in small spaces' we had a few men on the dry dock who could not do the work and threw they hand in, after the first day I did not like oil spills crude oil is very hard to shift when its cold with a shovel, Railway tanks are fine you can stand up in some? But every job has its probelms.Which you soon learn to sort out? I enjoyed my time working in the dry docks on all types of ships with a great bunch of men many like myself were ex merchant seamen

[Tony Morcom]

What is a railway tank? Never heard of that before.

[John Arton]

Off thread this but Louis the Amigo talking about his times in the Cardiff? drydocks reminded me of something I have always meant to ask if other members here have ever come across
In the late 90's there were two Norwegian ships that used to run into the Octel berth in the MSC and they would load the additive for leaded petrol there. Most of it went to places like India etc. This stuff was highly toxic and when the trade finished sometime after the turn of the century i think, the ships tanks were so impregnated with this stuff that the ships could not be used for anything else. One of the ships was actually two ships, the aft end being from a tanker that had suffered damage to its tank deck and its forward end (the cargo tanks) came from a ship that had suffered major engine room/accommodation damage.
The ships were beautifully maintained and spent days loading at Octel.
When the trade finally ceased the first ship was sent out to mid ocean and sunk but the hue and cry raised over the sinking of such a toxic ship meant that the second one could not suffer the same fate and was so laid up awaiting a descision of what to do with her.
Some years later we were having a class survey and I was talking to the L/R surveyor who was actually from the Cardiff office but had been seconded to Liverpool to provide cover. He mentioned these ships and we got talking about them and eventually it turned out that the second one had ended up in Cardiff where the boyos there had just ripped into it with the gas axes etc and demolished it no problema.
I expressed suprise at this as apart from being highly toxic the additive was also highly inflammable, hence the reason why no other ship breaking yard would handle it. Often wonder if anyone told that yard the exact nature of the ships cargo or did they know and just go ahead anyway.
rgds
JA

[John Arton]

Tony et al.
Its quite amazing what ships hulls can stand up to in a seway. Standing on the bridge of a VLCC or Cape sized bulker in heavy weather and seeing the main deck flex and bend as she went through the seas was a bit frightening but it seems to me that the worst stress put on these ships is actually in port when they are loading or discharging.
Ore ships have ore poured into them at a great rate from a huge height on loading and then have huge 40 ton plus grabs bashing them around when they are discharging.
On tankers the worst cases of structural failure have always seemed to have come after botched repairs or years of neglect.
Two cases spring to mind, the first one when a VLCC broke in half when alongside in Rotterdam. She had lightened in Le Havre and the daft mate had ltaken all the cargo out of the amidships tanks, she had then gone onto Rotterdam to finish discharge and it was only after they had tied up and connected the discharging lines and i think started the discharge, did she break in two.
The other was the Erika, I met a inspector who had tried to get her detained in her last loading port as he was so worried about the general state of her hull and the repairs that had been done on it but the port state would not assist him at all with the result that she loaded, sailed and broke in half in the Bay of Biscay.
rgds
JA

[Captain Kong]

When I was on VLCCs bound round the Cape to the Gulf Those big Cape swells really got the fore deck, 1000 feet in length, bending, it was amazing to watch. The strakes were made of high tensile steel and were designed to take it, or they would have snapped.
When loading or discharging we had a load master computer that showed the sheer forces and stresses in different tanks, so it was easy to plan before the start of load or discharge how much to load or discharge into each tank.
Brian

[Louis the Amigo]

Hi shipmates I did not just work in Cardiff dry docks but travel around south wales ports Barry , Newport swansea and also worked on the Railways sidings and most of the steelworks for the company Hi Tony A railway tank is a big round thingy ,some time square used to take liquid all types i,e oil chemicals , powder and stuff to where the driver takes' it maybe around the counry I only use to clean them , for repairs or safety checks or maybe change of cargo? I just done my job and had a wage at the end of the week, The foreman told me what to do , ours is not to reason why? but to do the job and ??? Ship tanks were classed as a good job because no foreman, or boss would go into one unless he had to.in my day.

[Gulliver]

Tony et al.....
The other was the Erika, I met a inspector who had tried to get her detained in her last loading port as he was so worried about the general state of her hull and the repairs that had been done on it but the port state would not assist him at all with the result that she loaded, sailed and broke in half in the Bay of Biscay.
rgds
JA

Thanks John,you know I can never resist looking up a casualty story,and I've pieced together a report on the ERIKA for us here.

ERIKA was a Maltese registered motor tanker of 37,282 dwt..She had been built new for Japanese owners in 1975,(SHINSEI MARU)and had a Succession of owners until renamed ERIKA in 1996.
On 12/12/99 in heavy weather ,this 24 year old ‘substandard’ vessel broke in half about 60nm off the Brittany coast.All crew were rescued and both sections separately taken in tow,but foundered the next day.
She had been carrying a cargo of 31,000 tonnes of Heavy Oil,and 20.000 tonnes of this was spilled,,the first oil reaching the beaches about 2 weeks later.Oil was still coming ashore reportedly until the following October.The main environmental casualty were seabirds,approximately 50,000 dying,although 2000 were cleaned up and released.There were numerous other claims from coastal fisheries,mariculture(oysters and mussels( industries and tourist facilities throughout southern Brittany and the Vendee.

Reported causes of the casualty : I. 'Classhopping' -refers to inadequate class control in view of the fact that a year earlier, in June 1998 the classification society BV refused to class her , calling her ‘unacceptable,‘ but subsequently another society RINA classed her as fit.
2. Hull failure occurred in a SBT due to heavy corrosion.There was a cargo leak from 3C to the uncoated SBT tank 2S. 4S deballasted. Cracking and buckling in way of 2S occurred ,sideshell unsupported,and 2S flooded.

As expected this casualty generated a ‘blizzard’ of paperwork by the IMO.
　
　

[Gulliver]

And here's the other case John(Arton) mentioned .I find them fascinating.

The s.t.ENERGY CONCENTRATION was a 212,269 dwt VLCC which arrived at Rotterdam after partial discharge at Le Havre. Her cargo was part crude, part fuel oil. Following another partial discharge at Europoort, she was to go to Immingham and complete discharge. She broke in half alongside after severely hogging. At the time of the failure (22/7/1980) a a total of 115,000 tons was still left in her tanks; however, the centre tanks and two ballast tanks alongside were both empty at the time .
43 crew members safely left the ship.

Cargo was eventually discharged, and the two sections towed away and broken up.The forepart was towed to Split and broken up 16/2/81 and the afterpart broken up Barcelona 16/4/81.

The Captain and Chief Officer were sentenced to four months for negligence by a Rotterdam court. The Master won on appeal; the C/O ended up being fined 10,000 guilders.
　
From the subsequent enquiry that followed the incident, it transpired that the sequence of discharging the cargo at Rotterdam was such as to increase the hogging moment above the already high value as a result of cargo transfer at the previous port of Antifer. The eventual distribution of weight and buoyancy induced a hogging bending moment which exceeded the ultimate longitudinal strength of the tanker.


　
Journal of Ship Research, Vol 40, No 1 March 1996, pp 60-69.
This casualty attracted all kinds of academic attention because it was a full scale experiment, a VLCC hull failure in which the loading conditions were well known. In this 1996 paper, Gordo, Guedes Soares, and Faulkner review the attempts to analyse this problem and present their own. In the as-built condition, the estimates of the hogging moment required to cause progressive hull failure range from 18979 to 20630 million N-m, with these author's estimate at 19164. The moment which actually failed the ship was 17940 MM N-m. If these numbers are right and the nearly 10 year old ship had not had any corrosion, the Chief Officer probably would have gotten away with his mistake. However, Gordo et al say :
The last survey report found all cargo and ballast tanks in good condition with the exception ballast tanks 3 where a greater degree of corrosion was found. The location of these tanks is coincident with the location of the failure.
The last survey was in late 1979, early 1980 at Singapore. or possibly in 1977 when the ship switched from DNV to BV, We of course dont have the Class survey data, nor do we know whether 3P and 3S were coated. In 1977, the ship switched from DNV to BV; we don't know why.
Anyway given the loading pattern, we only need a reduction in strength from the as-built condition of about 10 pct to generate a failure. Class rules allow 25 pct reduction in wastage before renewal is required, and in practice wastage worse than this is often not caught. It is not surprising that the hull failed.


　
　
Khan, Das, Parmentier, Ultimate Strength and Reliability of a VLCC
This VLCC broke her back in July, 1980 during a discharge of oil at Rotterdam. During the period Decmber 1979 to March 1980, the ten year old ship, Energy Concentration was surveyed by Bureau Veritas at Singapore. [One of the authors of this paper, Parmetier, is a BV employee.] It was found that all cargo and ballast tanks were in good condition, with the exception of ballast tanks No 3, where a greated degree of corrosion was found. The location of these tanks is coincident with location of the failure.
The last voyage of Energy Concentration was from the Persian Gulf to Rotterdam. The sequence of loading and discharging of the ship during this voyage was complicated by some changes of plans by the charterers, and by the need to carry five different grades of cargo, loaded at three ports for discharge at three other ports. Details of these transactions, including the ship's departure conditions from the Persian gulf and cargo discharges at Immingham and Antifer have been described in reference [1]. It may be noted here that the sequence of loading, dischaging and cargo transfer (exacerbated by the many grades of oil being carried) evidently led to the ship leaving Antifer on 20 July 1980, not only heavily trimmed by stern, but also with very severe hogging still water moment. The ship's drafts recorded in the deck logbook indicate a hog of about 43 cm. Subsequent calculations show that the ship commenced the final leg of the voyage from Antifer to Rotterdam with a still water bending moment more than twice the value permitted under the rules by which the ship was classed. The tanks were arranged in a 5x3 pattern plus two wing slop tanks aft. The three across were half sized and 3P and 3S were the segregated ballast tanks. The pictures show she failed just forward of the manifold, which would be in way of these tanks. The failure was in compression of the bottom structure. The deck folded at about Frame 76, but did not fracture.


　
　
　
CTX Database Comment
An extremely interesting structural failure which we must get to the bottom of. Was it a crew screw-up, or fatigue, or corrosion, or just an underbuilt structure? One reference is Rutherford and Caldwell, Ultimate Longitudinal Strength of Ships, SNAME 98:441-471,1990.
A glaringly obvious question is: why did the ship not put ballast in 3 wings before leaving Antifer?
Based on what we know now, sounds like the proximate cause was crew fatigue. A three port discharge with five parcels means two things:
Very little flexibility in how you handle the parcels and the order in which you discharge the tanks. The Chief Mate would not have been able to do things the way he normally would. Often these sort of cargos are accepted by the chartering people with no idea of the operational implications, or even if the cargo is indeed structurally doable. In this case, however, the inexplicable failure to start ballasting the midships permanent ballast tanks (3P and 3S) indicates that the Mate had not done all he could to minimize hogging stress.
No sleep. All three discharge ports are less than a days sailing from each other. In a normal discharge, there are calm times in the middle of the discharge where not much is happening, but with part discharges Chief Mates have no rest time. In situations like this the owner should put another Chief Officer onboard, but they rarely do.
Thank God, this ship had her cargo tanks inerted. (Newton, p 162). Otherwise could easily have been a Betelgeuse. (-Bantry Bay tanker explosion disaster 8.1.78)
No Oil spill is mentioned in ETC or other spill databases, so any spill must have been small, which seems strange, but indicates that the cargo tank in way of the midships ballast tanks was empty or nearly so. End.
　
　
　
　
　
　
　
　
　
　
　
　
　


　
　
　
　

[Tony Wilding]

i never realised the complexity of cargo handling on Tankers and Bulkers, its very interesting to someone who has not sailed on either, apart from a small coastal tanker, i now can see the proplems involved both loading and discharging. especially when different types of oil are carried to discharge in different Ports. must be a nightmare.