Minerva Concert aground off Sams

[Ploiarxos]

BlueWombat: "Especially since it is ALWAYS the responsibility of the master and that the master should have corrected any wrong order from the pilot."

WELL I AGREE WITH THIS but disagree with the crack existance before the grounding.
No any Ship can sail with a crack in her ballast due to flooding of the tank and due to list caused by flooding. Also will effect the trim...

[Mats]

The following is indisputable:
- A ship can sail along,
- a ballast tank can develop a crak,
- the damage can cause the vessel to list, develop increased draft or veer off course
- the vessel can as a result ground.

Whether this happened to "Minerva Concert" remains to be seen.

[Morten]

Ploiarxos wrote:

No any Ship can sail with a crack in her ballast due to flooding of the tank and due to list caused by flooding. Also will effect the trim...

A tanker carrying 81.000 mt of crude oil and a set of empty ballast tanks can easily sail with one flooded ballast tank. Especially when you think of this: If you have a direct access to the sea around you, the tank will fill until an equilibrium is reached and the tank will then become neutrally bouyant meaning a slight change in trim and draught, but nothing serious. This isn't even just basic seamanship, but basic physics.
But it didn't set sail with a cracked ballast tank. The companys CEO have said that the ship developed a crack causing it to veer off course. So while trim and stability would have been affected by the flooding, the ship would still have remained somewhat seaworthy, as long as the water isn't allowed to flow from one tank to another. And any stability issue could easily have been resolved by filling another ballast tank or move oil from one side to the other.

It seems strange that a ship only four years old can develop a crack, I'll give you that, but none the less, that is what the Minerva marine is claiming and it would explain the excessive manouever which could cause a grounding in that particular area.

[hmr170]

BlueWombat,  I was being sarcastic when I asked about a fracture affecting the vessel's maneuverability.  I am a former master mariner who served ten years on tankers and have spent the last ten years as a Surveyor for a major classification society.  I have been in hundreds of ballast and cargo tanks and most fractures in the sideshell or bottom plating will only let a tiny bit of water into the vessel (a trickle).  I can assure that almost all large vessels have fractures in their structure at any time.  Most fractures on tankers are located at the connection of transverse members to the longitudinal members.  It is rare for the fracture to propogate to the hull plating before it is detected and repaired.  For a vessel to have a fracture being so young, it is usually do to a hidden stress point.  The ships are designed around the class society rules which analyze the fatigue sensitivity of the structural connections.  Sometimes, a localized area will experience a fatigue fracture due to mis-alignment of structural members during construction.  A fracture in the hull will in no way affect the maneuverability of the vessel.  

If an empty ballast tank was flooded to the point where it had reached equilibrium with the outside water level, it would most certainly develop a large list.  If the vessel was completely loaded with cargo, there is no room for any ballast.  A ship cannot sail with its ballast tanks and cargo tanks full.  It would most certainly break in half and sink.  It would make a difference where the ballast was located (fore and aft) before I would make the statement that it could sail with one tank flooded.  I would not want to have a ballast tank flooded if it was located in the mid area of the vessel.  The stresses would be enormous.  If the vessel was not completely loaded, then some ballast could be carried, so long as the loadline was not exceeded and the hull stresses were not exceeded.  No master would go to sea with any unexpected changes in the list or trim.

[Aleksi Lindström]

It seems that the tanker to which some oil will be lightened from the Minerva Concert is the BRO SINCERO, IMO 9254422.

Brgds,
Aleksi

[Tore Christiansen]

Strange, but she must have switched off her compulsory AIS transponder as she is not visible at all anywhere near Samsoe?

Have a look:
http://aisserver.yachtmarine.com/SAMSOE.html

Sorry, I didn

[spotti]

At least three tugs: STEVNS OCEAN, AROS and HERMES.
The last two are harbour tugs from the Port of Aarhus.

[Ivan Egeriis]

She is off the ground and underway to Kalundborg Fjord

Kind regards

Ivan

[Tore Christiansen]

Hi Ivan..

Yes, that would explain the difference in position, she
is no longer aground..

By the way, your AIS was 3 days out of date when I updated it...

Regards
Tore

[Morten]

Hmr170, I have a question for you:

When was the last time a crude oil carrier broke up because of a flooded ballast tank? Anyone? No? Didn't think so... Standards for crude oil carriers have become very high after a few "minor" incidents (Amoco Cadiz, Torrey Canyon, Prestige, Exxon Valdez etc.)... I shouldn't have to tell a class surveyor and educated sailor this! It is true that a ship loaded unevenly could break up due to excessive sheer force, if the forces were very big and the ship encountered rough weather. But no sailor, ABSOLUTELY NONE, would ever set out knowing that they had major stability issues, I think we can all agree on that, none the less, the operator have said that the ship developed a crack and this resulted in the ship veering off course. This shouldn't even be up for debate... It is indisputeable facts. What can be discussed is how the company can possibly admit that the ship veered off course due to a cracked ballast tank, but still blame the pilots!

Another indisputeable fact is that a leak will affect the manoeuvering characteristics of the ship, especially if the leak is caused by an external crack and even more so if the crack appears in the forward part of the hull! hmr, you said yourself that the draught and trim and it will affect the heeling of the ship... But you claim that a leak won't affect the manoeuvering... How does that hold together?

[hmr170]

BlueWombat,  

A fracture on a ship is usually hard to see with the human eye.  The usual tell tale signs are some rust streaks or active corrosion in an otherwise epoxy coated tank.  You usually have to chip the area with a hammer to see the fracture.  They may or may not be in compression due to the loaded condition of the vessel and where it is actually located.  We are not talking about gaping holes in the hulls.  Like I said before, the amount of water ingress or outgress (depending on where it is located) is almost insignificant in the scheme of things.  I don't know what else to say if you do not understand the operations of a vessel.  I enjoy this forum and I am glad to see that people take such an interest in maritime affairs, but if someone posts erroneous information, I feel obliged to point any errors.  

Vessels are not really built any stronger than they were 30 or 40 years ago.  Technology had actually allowed designers to build vessels with lighter scantlings, in essence, less robust ships.  Prior to the technological advances, they designed them based upon experience and they definitely erred on the conservative side.  The saying "They don't make them like they used to" definitely applies to ships.  Shipyards and classification societies competed with each other by offering the lightest (scantling wise) ships they could get away with because the less steel you use in the construction, the cheaper it is to produce.  Advancements have been made in the design of end connection details to reduce the number of fractures a vessel would experience.

Tankers actually are not that concerned with stability like a dry cargo vessel.  The vessels are inherently stable and you do not even calculate the stability of a tanker for normal operations as you would with a container vessel or dry cargo ship.  Tankers are really concerned with the sheer forces and bending moments.

As for vessels breaking up, why don't you ask the Master of Erika or the Prestige if counterflooding the ballast tanks or transferring cargo from one wing to another was a good idea to control list.

[mooringman]

the "Minerva Concert" is at anchor kalundborg road and they will sure make a survey.they will find out the reason for the accident and i hope they will tell us the truth.i think,she has only part cargo.
i just think,a crack in the ballast tank can't be the reason for the grounding.this is stupid talking.but we will see....
by the way,i know from what i'm talking.i was myself for 37 years at sea as os up to captain and a lot of different ships from a vlcc to a tugboat....and i know the area very well.

[Morten]

Okay, now this is just getting silly!

hmr170...
Have you even read the requirements for damaged stability for a tanker?! There are very specific requirements they have to meet! And class specifications doesn't mean anything here, because they have to, at least, meet the IMO criteria and are usually set higher (since a ship can't enter 98% of territorial waters unless it meets IMO requirements making sea travel very hard).

As to the accidents mentioned: Erika broke up due to heavy corrosion in the tanks... Not ballasting. The exact same thing happened to the Prestige which was known to have several severe structural deficiencies prior to the final voyage and had not undergone proper inspection and vetting (read an accident investigation report)! It had a huge gaping hole caused by an external force (rough weather and high seas). Both were single hulled and both had servere structural damage. Ballast was only applied after the structural damage had occured and was done as a meassure of stabilizing the ships so they could be towed to calmer waters. Had the ships been in good condition (the Erika was thought to be, but actually wasn't), a flooded ballast tank wouldn't have been that big a deal (again, read the requirements for damaged stability). A flooded cargo tank however will have a HUGE influence on the stability and structural integrity of the ship due to the size of the tank and the higher density of water.

But we are not talking about a ship with serious structural damages here. We are talking about a double hulled ship which developed a leak that allowed water to fill a ballast tank in minutes not hours or days! If you have ever sailed on a ship with computerized control (ICS) you will know that it is very easy to detect such a leak since the system will give an alarm as soon as it detects a considerably different water level than the preset one!
I do not know what the cause of the leak was, but a leak of this size can, and did, occur causing the ship to veer off course, that is an indisputeable fact... It is pretty obvious that we are not talking about a corrosion related fracture here (it can however very well be stress related, since stress related fractures can be many things). If you don't believe that this can happen, well, that is your problem, I know and have seen it happen (never tried it myself fortunately, but I've seen ships where similar things have happened)... Again, if you really don't think that a flooding of a tank can't alter the course of a ship, you need to read up on your seamanship!

And still, I have yet to see an example where a tanker have broken up due to a flooded ballast tank! If that was all it takes, we would have broken up oil tankers lying all over the ocean floor! If a hull plating is compromised by a crack, it's strength is greatly reduced, and a direct hit by a wave could make it buckle giving direct and virtually unrestricted access to the tank behind it (I haven't eer seen a cracked hull plating myself, even after a close encounter with a tug boat in Jeddah, but I guess it does occur). I don't even need to have experienced a crack to know that, that is all physics...

Ohh... And as to the sheer force and bending moments... The notion that sheer forces and bending moment isn't that big a deal onboard container ships couldn't be more wrong! Just look at the MSC Napoli! I've sailed on ccontainer ships, and one of our biggest concerns during loading, is to reduce sheer force and bending moment to a minimum because of the weightdifferences of individual containers (stability is usually not an issue)! Because unlike an oil tanker, we can't just move some cargo from one tank to another to alter the moments. If you are ever onboard a M