Alternate Hold Loading in Bulk Carriers - Ships Nostalgia
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Alternate Hold Loading in Bulk Carriers

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  #1  
Old 2nd May 2007, 18:57
Hague Hague is offline
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Alternate Hold Loading in Bulk Carriers

It would be interesting to hear the views of those who had experience of this loading technique. I believe it would develop into something interesting.
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  #2  
Old 2nd May 2007, 20:38
John Cassels John Cassels is offline  
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Am preparing my contribution. This can sure be an interesting thread.
Well done Hague.
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  #3  
Old 3rd May 2007, 09:21
John Cassels John Cassels is offline  
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The title should possibly be "Alternate hold loading of Ore in bulk carriers ".

As far as I am concerned , the reason for this practice was purely commercial.
Promoted by discharge and loading terminals to reduce the number of shifts
of men and equipment and hence speed up loading/discharging rates.

Promoted by charterers ( both time and voyage) to reduce cleaning time and
hence cleaning costs. Most charter partys call for a vessel to be delivered
"swept clean and free from previous cargo residues" - in the ore trade.

How much this practice has contributed to marine accidents is something that
can be discussed for ages but my view is that it was certainly was never to
the benefit of bulk carriers or the personnel on board.
The only advantages I can see are the reduction of that back breaking work
of hauling up and dumping hundreds of buckets of ore sweepings and a lot
less hold to survey for grab damage . But these are far removed from the
safety aspect.

Have been involved in this subject as ch.off , then as owners/charterers rep.
so have seen it from both sides and once had to convince a Master on one of
our chartered bulk carriers that the practice was completely safe - a task I am not particularly proud that I succeeded.
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  #4  
Old 3rd May 2007, 09:39
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John

having experienced a lot of this practice myself, I take and agree your points-- but not necessarily the reference to just ore loading. I think it is being overlooked that it was common practice in larger bulk carriers when in lightship passage to fully ballast just ONE hold, something in the order of 20+k tonnes water ballast-- if my memory serves me well, generally No6, ie around mid-point of the ship's length-- with the facility to also ballast 2,4,8 in some ships in which I sailed, though not necessarily to hatch coaming depth-- thus, similar shearing forces at the frames between holds as in, for example loading, 1,3,5,7,9, with 2,4,6,8 empty, would, on the ballast passage, be also applied, but only in ONE section of the hull structure rather than five.
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  #5  
Old 3rd May 2007, 09:59
John Cassels John Cassels is offline  
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Quote:
Originally Posted by john shaw View Post
John

having experienced a lot of this practice myself, I take and agree your points-- but not necessarily the reference to just ore loading. I think it is being overlooked that it was common practice in larger bulk carriers when in lightship passage to fully ballast just ONE hold, something in the order of 20+k tonnes water ballast-- if my memory serves me well, generally No6, ie around mid-point of the ship's length-- with the facility to also ballast 2,4,8 in some ships in which I sailed, though not necessarily to hatch coaming depth-- thus, similar shearing forces at the frames between holds as in, for example loading, 1,3,5,7,9, with 2,4,6,8 empty, would, on the ballast passage, be also applied, but only in ONE section of the hull structure rather than five.

Well , of course you are correct John but my point was really that ships and
personnel were forced into this loading practice through commercial pressures
in which safety took a back seat. Ballasting holds at sea , although approved
of in the stability book was only necessary if required by the vessel.
Bye the bye , never liked the idea of half ballasting a hold especially in any sort of weather.
Will we ever find out what the long term effects of this practice have ( and )
will produce ?.

Interesting thread this .
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  #6  
Old 3rd May 2007, 11:17
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Alternate Loading

Hi All
Sailed in "Derbyshire" class OBO "English Bridge" We took this vessel from new from the NE Coast. Alternate Loading and Ballasting was used in these ships. Even as just the R/O, I could visualise in my minds eye the tremendous upwards thrust of the boyant empty holds compared with the downwards thrust of the loaded ones. However, we were confidently told that these ships were specifically designed to be loaded in this way, is this true?

Alan
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  #7  
Old 3rd May 2007, 17:14
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Alan:

-- I think that's pretty much the point of this thread-- we ALL were reassured of the same, though our input of ship stability and ship construction tended to point in other directions, shall we say? I'm not sure whether you are aware of, or been party to, the "frame 65" issue re the class of ship you mention, but a search of the SN site will bring up some interesting remarks and links

John:

-- I agree wholeheartedly with all you posted, and hope I did not appear to differ. The driver in most things was, and probably still is, money and profit, of which time taken loading/discharging/repairing grab damage represented a significant proportion. I merely sought to point out that these shearing forces could be applied to such vessels virtually daily throughout their lifetimes,whether laden or not.

As to partially ballasted holds, I concur absolutely--- I recall only ever using this facility to combat air draught restrictions. The thought of the free surface effect, in any sort of a seaway, in the holds of a Cape size bulker for example scares the hell out of me!!

Thankfully, I am unaware of any examples of negative impact of the alternate loading/ballasting operations on any of those ships in which I sailed-- and I'm still here, unlike many unfortunates. As you say, we will probably never know, but very interesting nonetheless.
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Old 3rd May 2007, 19:33
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All,
On a similar theme, on leaving Port Elizabeth SA with a full cargo of Manganese, on a Bulk Carrier whose name begins with A. the Mate would top up a couple of sets of the upper wing/saddle tanks to improve the comfort on the voyage home and obviously pumping out prior to arrival.
I assume this would be a Capital Offence today?, it probably was then!!
Yours aye,
Slick
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  #9  
Old 3rd May 2007, 19:57
John Cassels John Cassels is offline  
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John , did not take it that you were trying to differ , I knew where you were
going and you are right , same degree of forces would be present.

As for partially flooded holds. Happened to me once as mate on an OBO.
We ended up having to do some "nasty "things" cleaning from oil to coal.
To cut a long story short , we ended up with No.5 covers open and the
hold at about 70% when the ME stopped and the ship broached too.
The noise and forces created by that free ballast you would not have
believed, frightening .

I am also not aware of any impact of alternate hold loading buy am sure they
are out there somewhere.
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  #10  
Old 3rd May 2007, 22:27
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Slick........when sailing with a certain Arabian Outfit with many ships names beginning with "I" we would normally load a gut full of Steel and with a bit of General on top we would set out for the Arabian Gulf. Upon sailing the Mate would fill at least two of the Upper ballast tank and possibly all four which gave us a more peaceful passage across the N.Atlantic. Before arrival at Suez this would be pumped out for the canal passage and depending on the season replaced on passage down the Red Sea. This would be pumped out on arrival Hormuz. Crime?? Hell Yes, but at least you could sleepwell............pete
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  #11  
Old 3rd May 2007, 23:06
Hague Hague is offline
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John,
Would agree with your initiating premise that this practice has its origins in commercial considerations however, there were several Ore ports where the practice was conceived out of operational considerations such as air draft and conveyor restrictions. I am thinking of Nouhadibou (Port Etienne) as an example which had such a long conveyor system which necessitated clearing the belt before a shift could be initiated. This same operation was responsible for 'overloading' as, if you ordered say 6000 tonnes for completion then you were going to get that amount at least 'like it or not'. Places like Sepitiba produced other problems such as accelerated forces generated by loading at 15000 per hour compounded by SF which were off the scale on the Loadmaster and BMs giving off the scale Hogging induced by the alternate hold loading. I never liked the practice. Did I ever load in that fashion yes. BISCO used to specify alternate holds for single grade from Nouhadibou (TZT) ,Seven Island or Port Cartier.
Generally two grades loaded in Sepetiba ( Itabira Fines....Redcar 2,4,6,8,) and Itabira Pellets (Immingham 1,3,5,7,9,,).
So, the practice had an element of both but should never have been recommended by Charterers. I have an uneasy feeling about the loss of several Ore Carriers loaded in this fashion which may have survived if loaded more homogeneously ( all holds)

Last edited by Hague : 3rd May 2007 at 23:23.
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  #12  
Old 4th May 2007, 11:16
Ventry Ventry is offline  
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Gentlemen,
When the charterer orders alternate hold loading it is difficult to argue. Clearly, they had a vested interest in the loadport and disport to turn the vessel around asap. Ref forces induced due accelerated loading is interesting.
Having loaded Sepetiba on Ore Oil Carriers at the rates mentioned above I was always concerned at the tremendous vibrations experienced and the unseen effect it had on the tank top structures. On the odd occasion that orders were specific to load alternate holds I used to 'protest' to everybody who would listen (Sparky worked overtime). Unfortunately, the arguement back from Charterers and Ops was the the T/C description of the vessel stated by class for '2,4,6, & 8 may be empty'. Rather strange that Japanese Charterers never issued such directives/orders and knowing the mentality of the Japanese Master's I relieved they would ignore such directive in any case and load all holds.

Last edited by Ventry : 4th May 2007 at 12:26.
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  #13  
Old 4th May 2007, 20:58
Hague Hague is offline
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Not an expert on the subject but I understand that the stresses induced by accelerated loading is aggravated by the the direct overboard discharge (hence rapid) of the TSTks which a lot of the Cape size vessels have. The natural harmonics (vibrations) work against each other and have a cumulative effect rather than, as one would think, cancel each other out.
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  #14  
Old 5th May 2007, 09:53
John Cassels John Cassels is offline  
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In my experience it was the rule rather than the exception to load alternate
hold unless , as Hague points out , more than one grade was to be loaded.

Whilst it may be difficult to prove that alternate hold loading has caused
shipping losses , even the most unseamanlike person ( like my wife ) has
commented that loading and discharging alternate holds year in , year out
cannot be construed as being beneficial to any bulk carrier. There must be
a gradual weakening of the hull structure.

On a similar vein , remember being on one of the earlier panamax bulkers as
3rd.mate in the mid '60's , and being hove too in a bit of a blow. One could
stand on the bridge and watch the forrard end flexing up and down.
When I asked the old man , remember he answered not to worry as the
sheer strake was special high tensile steel . H'mmmmmmmmmmmmmmmmmmmm
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  #15  
Old 5th May 2007, 10:15
Hague Hague is offline
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In other words. Don't worry the special High Tensile Steel fails without any warning and it will all be over very quickly!
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