Load/underload

[happy daze john in oz]

Down in Port Melbourne at the weekend and saw a large container ship arriving from the southern ocean.The top deck was fully loaded with containers, just about as many as she could carry on deck.
The odd thing was though her amount of freeboard.
A two coulored hull with the plimsol line at the join of the two coulors.
From that line to the water about three metres, it appeared as if she had no cargo below deck.
Is it common for container ships to travel in this manner, would consider such an arrangement would effect her centre of gravity

[John Arton]

John in OZ
It could be that the majority of those containers on deck were empties being re-positioned. Its always a major problem for container lines to get their empties back to the part of the world where they can be used for cargo. An empty container does not attract any freight so they are invariably stowed on deck, leaving below deck stowage for money earners.
It was always said that the EVERGREEN line ships always looked full as they would fill there decks with empty evergreen containers.
As a further aside, there is a feeder container line in Europe where all the ships are named after and painted in the colours of, German football Clubs, Borissa Dortmund etc.
They actually sell advertising space on the side of the ships accommodation and a German pilot friend of mine told me there was one outfit that had roller blinds fitted all the way down the deck sides on the container ships, where once they picked up the pilot they would press a button and these huge blinds would come down revealing adverts for all sorts of commodities. I once suggested this to my owners (Beer Sponsorship?) as a way of earning extra dosh, it did not go down too well though, cannot think why.
rgds
JA

[j.sabourn]

John in Oz. I never had the fortune or misfortune to sail on purpose built container ships. To me however they always seem to have a lot of freeboard so assume they are never down to their marks, I maybe wrong in this no doubt people who have sailed on such will know. I wouldn't even know how many tween decks they have (if any). When Samuel Plimsoll introduced the plimsoll marks on vessels this was for the safety of the people onboard and assume he had thoughts of ships with low freeboards taken on seas and foundering. To me they do not affect the stability of the vessel as modern present day vessels can easily lower their centre of gravity by means of ballast tanks, and with not being down to their marks is easy enough to accomplish. This does not apply however to a cargo vessel down to her marks, and the loading has to be in accordance with stability standards usually set up by the government departments concerned, especially with the likes of grain which has a free surface effect. What I see of modern day ships they try to build them idiot proof, however we still seem to get the same if not more disasters re shipping. Perhaps the Fremantle Dockers didn't work out their stability correctly, still there is always next year. Cheers John Sabourn

[John Arton]

These mega container ships, and even those going back to 2nd generation, are all double hulled with ballast carried in the side tanks formed by the double hulls and fuel and ballast in the double bottom tanks. This gives them good longitudinal strength but the problem is building sufficient transverse strength to avoid torsional (racking) stress. The holds are just huge empty shells filled with cell guides. At every 80 ft there will most likely be a perforated bulkhead that will carry services for reefer containers and allow for inspection of same reefer machinery. On top of that there will be solid transverse bulkheads at intervals to ensure damaged stability requirements are met. You can see that on the latest ones the bridge and accommodation is positioned about 1/3rd length with the engine room around 3/4 l. This is for a number of reasons.
Where the bridge/accommodation is situated it is not possible to put cargo underneath so that space is used for bunkers etc. meaning that so have a strong transverse section of hull. Also the bridge needs to be situated there to comply with forward visibility requirements as set out by the IMO. Again with the engine room this again provides a strong transverse section but just as importantly it means that the propeller shaft is of a reasonable length but still needs huge intermediate support bearings.
rgds
JA

[Tony Wilding]

it must be a nightmare loading a ship, especially if Container Weights are fiddled, that seems to be the Achilles Heel of such ships, plus of course unstated dangerous contents of Containers,

[John Arton]

Tony
re. container declared weights.
It is a huge problem. The European Union has just rejected an IMO motion that all containers be weighed at the terminal entrance using the fact that transhipment containers would avoid this requirement. Instead they have reverted to saying that when the container is filled and sealed at the stuffing depot then it should be weighed as is the case and its therefore up to the stuffing depot to not falsify weight declarations. The thinking being that once those container doors have been shut and locked with the seal on them then nothing can alter the weight without the seal being broken, which could/should be picked up at the container terminal.
This pre-supposes that all stuffing depots are run by honest truthful guys. As the majority of the overweight containers come from countries where baksheesh is a way of life, this is typical European short sightedness and will do nothing to prevent the occurrence of large numbers of containers being overweight. On these mega container ships with up to 18,000 containers on board if only 5% of containers are overweight by half a ton that is 450 tons, which may not show up too much on the draught marks (don't know the TPC of these beasts but it must be well over 100ton/cm) and anyway do they even bother to accurately read departure draughts or do they just record the draughts as given by the loading calculator whose input weights are given from the declared weights.
A number of modern container terminals have scales on the crane but what can that do. The scales are their to ensure that the crane is not lifting more than its swl, its not there as a check on the actual weight as opposed to the declared weight.
So until all containers are weighed on a weighbridge at the terminal and the weighbridge operators are not open to bribery and corruption, overweight containers are most likely to stay with us and the resulting possible overstressing of ships will continue.
rgds
JA

[Keith Tindell]

The other problem with the containers is in the event of chemical leakage from within the container or fire, alongside still a problem with off loading until you can get to the container, and deal with it. At sea a whole new ball game . These things are not stacked with the dodgy contents on the top, but can be several deep.regards KT

[Captain Kong]

There is a program on TV in the UK on Tuesday 10pm, chan. 38 Quest. all about the big ones, 18,000 units.
I have never ever sailed with a container and so know nothing about them.
Brian.

[Louis the Amigo]

Hi shipmates, I was long gone , before the box boats and the quick turnaround, it was just talk in them days still on the drawing board? am i glad i missed it yes sir

[Jim Brady]

I suppose you could have the full 1800 containers filled with "cornflakes" what weight would that be.For instance I know of one container with just a set of rotor blades off one helicopter so I suppose its swings and roundabouts with overweight and underweight being loaded.
Regards.
Jim.B.