CARGO MOVEMENT - OPEN TOP CONTAINERS

Dear (s)


{I started this blog during Sept 2009. This article on Open Top Containers was shared with my friends on 5th Sept 2008 at which time, there were news items of this container type being very new to the market. The article reproduced now with some modifications and posted on my blog.}




For those of you who have been on ships and have handled containers for ages – this info may be rudimentary. Whilst this appears innovative, there are some questions like : is the risk of theft higher on such containers? will these containers also be sealed in the normal manner? When somebody can approach by cutting from top, is it fool proof to have strong doors? I don’t have ready made answers but still found it worthwhile and interesting about this new type of containers – Open Top containers.

Goods are transported from once place to another - often across Nations - perhaps almost any product that humans utilize spends sometime in a container. As goods are so transported, they require robust packaging to withstand the vagaries of transportation. The primary purpose of packing is to protect them from possible damages. The introduction of containers has vastly improved the way the goods are handled, transported as mostly the cargo within remains untouched during the journey.


There are five common standard lengths, 20-ft, 40-ft, 45-ft, 48-ft, and 53-ft. The majority of containers used worldwide today comply with the ISO standard, with 20'- and 40'-long containers predominating the development of standardized has ensured that cargoes, sometimes of different characters are shipped together easily. As the containers are stacked one upon the other, it is huge savings on space and costs. The exterior dimensions are generally 20 X 8X 8.6 Apart from the size there are various types: Standard, High cube, Hard top, Open top, flat track, platform, Refrigerated, Bulk and Tank containers. - To name a few. This is how containers are stacked.

The container floor is generally made of wood, usually planking or plywood. The sides are made up of corrugated steel sheets / aluminum sheet in conjunction with stiffening profiles. This is something about a new innovative type known as Open top which as the same suggests will have opening on top. This will be very easy to pack and unpack from the above using cranes or crab. They will be closed with tarpaulin. They are suitable for transporting over height cargo i.e., cargo taller than 2.54m /8'5".Commodities commonly shipped in the open top container include machinery, industrial boilers, tractors, steel pipes, steel bars and cables.


Read recently about a futuristic invention in the container transport: a new sliding open top container - developed in South Korea. This promises to overcome drawbacks associated with earlier designs at a cost that represents only a marginal increase over that of a standard open top. This is developed and patented by a company owned by former Hanjin Executive.

Open top units are designed to allow loading through both the top opening and the rear doors and are consequently suitable for the carriage of awkward and indivisible cargoes, whose handling and loading can only be performed with a crane or rolling bridge. Tiltable half-height open top containers are specifically designed to carry bulk minerals. The roof is replaced by a tarpaulin to allow loading and discharge from above. The tarpaulin covering means cargo is fully protected from the elements. Manufactured from steel, open top containers come in 20 ft and 40 ft sizes. Open tops are equipped with a swinging header to the door opening, hinged doors on both sides and removable roof bows and tarpaulin.

A safer and more cost-effective design of open top container - designated the “Sliding Open Top” - has been developed by Korean container specialists BoxJoin Corporation. The innovative design is being marketed internationally to container shipping lines, leasing companies and intermodal operators by Blue Sky Intermodal (UK) Ltd, on behalf of BoxJoin.

Open top containers are commonly used in the container shipping industry to transport oversized cargo and cargo which cannot easily be loaded into standard 20ft or 40ft dry freight containers through the doors. Instead of a normal container roof, an open top container is fitted with a removable tarpaulin, supported by a series of roof bows. Major challenges for container operators are how to easily open and close the roof, and how to avoid losing the removable parts, (the tarpaulin and roof bows) once the cargo has been discharged from the container.
BoxJoin’s concept is for the roof bows and tarpaulin to stay with the container. Instead of the roof bows being secured by pins in the top rail (as on a standard open top), the roof bows on the new Sliding Open Top have rollers at each end, which sit in a track on the inside of the container’s top rail, running the whole length of the unit.   So, after the rope securing the tarpaulin to the container has been untied, the roof bows and the tarpaulin together can now be pulled along the track either to the front or back of the container, giving access for quick and easy loading and discharging of the cargo. Alternatively, the roof bows can be pulled along the track after the tarpaulin has been pulled back in the same way as on a normal open top. The roof bows are held an equal distance apart from each other by a simple cord. To pull the roof bows backwards and forwards, a hand rope is attached at both sides of the first and last roof bow ends. When the roof is closed, the hand ropes can be tied to the four corner posts’ inner lashing bars, to prevent the roof bows moving in transit.

If the roof bows have to be removed, they can easily be taken out of the track on the top rail through a slot at each end of track and then stowed on the front wall of the container, behind a simple securing bar that is installed in both inside front corner posts.
One of the main benefits of the system is that it avoids the need to remove the roof bows and the tarpaulin during loading and discharge, so there is much less chance of them being lost or damaged. In addition, there is no need for people to climb up onto the top rail to remove the roof bows. Operations are therefore much safer, because the roof bows and tarpaulin together can be pulled up and down the track either from inside the container or from alongside the container with a rope. Trials have also shown that cargo loading and discharge is much quicker than with a normal open top.


In the original version, specially designed roof bow ends ran on rollers in tracks in the top side rails and were connected by a scissor mechanism, which ensured that they were correctly spaced and could not jam in the tracks. The tarpaulin was attached to each roof bow and once detached from the top rails and headers, the tarpaulin and roof bows could be rolled back concertina-fashion to the front end of the container like the hood of a soft top car. There were some troubles experienced including the restriction of loading area by the retracted tarpaulin at one end of container and thus


For the not so informed, the maximum permissible weight (called Rating) i.e., weight of a container + its contents of a 20' dry cargo is 24000 kgs and for a 40' is 30480 kgs.


With Regards
S Sampathkumar