Supramax Cargo Vessels: The value of the cargo sector is in the trillions. A wide range of items are transported worldwide, from fresh food to airplane parts.
Hundreds of ships that travel the world’s oceans are essential to the global shipping industry’s success. They range in size from little speed boats and fishing trawlers to enormous monsters like Heavy Lift Vessels (HLVs).
Bulk cargo carriers are a different class of boats that are utilized for shipping in addition to container ships. These boats transport loose goods in large quantities without segregating them like container boats do.
The Supramax class of ships is one example of this kind of cargo ship.
Although they are thought to be somewhat smaller than bulk carriers, they are nonetheless frequently seen in use all over the world.
What are Supramax cargo vessels?
Loose and unpackaged products and items are referred to as bulk freight. Think about the container class of ships to get a sense of this. Container ships quantify their cargo in terms of carrying units. This might be kept in boxes, pallets, crates, etc.
One important requirement for items transported in containers is that they must be kept in certain conditions the entire way. It is not appropriate to handle a crate of beverage cans by hand, for example, as this could lead to a rapid depressurization and eventual gas release during transportation. As a result, they are kept within containers on pallets.
In the same way, fresh produce cannot be merely stored in a container in a loose state because they would bruise and abrade during shipping. They are kept in specific storage boxes that have an outer layer of protection. As a result, items that need to be stored steadily are transported by container ships.
Thus, the challenge of how to carry an infinite good, like rice, emerges. It is impossible to quantify rice in terms of individual grains. Rather, we calculate the quantity being delivered using a weighted approach.
It would be a headache to load and unload rice into a container if we were to transport it that way. Grains would become stuck in every crevice and may move while traveling. Because of this, opening the container doors at the destination would be risky.
A kind of boats called as bulk carriers is more convenient to use as they can store vast quantities of loose products, saving plastic that would otherwise be wasted trying to package rice into more manageable units. Materials like loose grains, ore, cement, etc. are frequently transported with them. The items are kept in the hatches that are located beneath the deck. Cranes located on the upper deck are used to carry out operations.
Depending on their size and itineraries, bulk freight carriers are categorized into numerous size classes. These are Aframax, Chinamax, Panamax, QMax (Qatar-max size), and Suezmax, which are designated according to the regions they can pass through due to dimension limitations.
There are several types based on nominal sizes, including Handymax and Supramax.
The Supramax Carrier: Dimensions and Details
Although the terms Handymax and Supramax are frequently used interchangeably, they differ significantly. While the Supramax class includes boats with tonnage ranging from 50,000 to 60,000 DWT, which makes them larger than Panamax carriers but less than the largest bulk carriers, the Handymax class consists of vessels with tonnage ranging from 35,000 to 50,000 DWT. Among the essential characteristics of a Supramax bulk carrier are:
- Length: 180-200 meters
- Beam: 32-35 meters
- Draft: 11-14 meters
It should be noted that deadweight tonnage refers to the weight of the maximum load a ship can carry, excluding the weight of the ship and its machinery. Rather, it consists of the cargo, fuel, ballast water, and other components.
The Supramax boats’ very small size makes them appealing. They can be 150 to 200 meters long and are ideal for docking at ports all over the world. These ships are among the most popular ones in the size category above 10,000 DWT. Because of their size, they can pass through most locks and canals that would be inaccessible to other ships.
For example, there are stringent limitations on the size of ships that can pass through the Panama and Suez canals. In actuality, this led to the creation of the New-Panamax and Suezmax class of vessels.
Crossing these straits and canals is easy for supramax vessels. It is noteworthy that modifications are being made to Handymax ships so they can accommodate up to 55,000 DWT of cargo. This is a result of the sustained high demand for supramax boats. These kinds of vessels are in demand, but production takes a while.
These ships have several holds, which allows them to carry a variety of goods. As an example, it is typical to have three or four holds full of ore and the remaining holds full of grains.
Royal Caribbean Places Order for New Cruise Ship at Chantiers de l’Atlantique
Along the way, some holds might need to be unloaded at a port depending on the itinerary and logistical needs. Another cargo is subsequently loaded into these empty holds and needs to be unloaded at the destination.
Supramax vessels are advantageous for international shipping due to their versatility. In fact, most Handymax vessels are upgraded to meet Supramax criteria because of the great demand for these ships. In actuality, upgraded Handymax carriers make up close to 80% of the Supramax fleet worldwide.
A growing number of Handymax ships were built in shipyards in Korea and Japan during the 2008 economic boom. At the time, the cost to create such a vessel was close to 40 million USD.
After the numerous financial crises of the next decades, the price has dropped a little, and a Supramax or Handymax vessel now costs between $25 and $30 million USD.
Plan and Configuration of Supramax Crafts
In general, a superstructure is found near the stern, starting from the upper deck. The bridge, equipment, and crew rooms are all housed in this building. Supramax ships typically have conventional superstructures that are 40 to 50 feet high. There are deck cranes and hatch coverings in the remaining section of the upper deck.
Typically, traditional ships have five watertight hatches. Hydraulic systems extending along the upper deck’s edge are used to open the hatch coverings. In order to strengthen the hatch opening and increase strength, high scantling members are sometimes installed for support.
On the upper deck, there are often four cranes. They assist with some sorts of items’ loading and unloading. When a Supramax ship berths at a port without fully functional crane facilities, this is quite helpful.
The vessel has a quicker turnaround time in certain circumstances. Cranes on Supramax ships can lift an average of about thirty tons. The cranes that are utilized are frequently double-articulating models.
The maximum draft on bigger vessels is approximately 13 meters, whilst smaller models have a maximum draft of 10 to 12 meters. A contemporary Supramax vessel’s dimensions are as follows: 199 meters for overall length, 32 meters for beam, 12.2 meters for draft, and 18.8 meters for depth.
The engine compartment, which is situated beneath the main superstructure, is where the machinery portion is mostly housed. Here are the engine and propeller shafts, which are situated on specially designed platforms meant to dampen vibrations and shocks. The most popular engine is a fixed-pitch propeller paired with a twin-stroke marine diesel engine.
Two four-stroke engines are used in modern smaller ship types to power variable pitch propellers. There are numerous additional auxiliary machines positioned in and around this area. Systems such as hydraulics and others often run the length of the ship inside the hull side shell. Provisions are created for the anchor machinery at the bow.
Now let’s examine the hull and holds’ structural makeup. The ship’s twin bottom adds to the overall torsional stiffness of the craft. In the case of a mishap, it also stops liquid and gaseous cargo from leaking. The bulkhead framing supports a single hull on the majority of boats.
On the other hand, having a side shell is recommended for vessels with fewer holds as it increases the vessel’s rigidity. A single hull structure is the simplest to construct. In a similar vein, a vertical section that slices through the water frequently replaces the bulbous bow at the front.
Effective modelling of the remaining part of the hull reduces wave resistance. For bulk carriers, the block coefficient—a metric used to gauge a vessel’s capacity—is quite high.
This makes them sail more slowly, but they are more efficient since they can carry a lot of cargo.
Bulk carriers are further distinguished by their inwardly sloping hulls, which are located close to the bilge. This keeps materials from building up and permits ballast water to be stored in the space next to the bilge.
Running of Supramax Ships
Depending on their main route and the kind of cargo they carry, supramax ships might operate differently. For example, the number of crew members on such ships can range from ten to about thirty.
Many workers are frequently needed for maintenance and repairs on the larger types. However, small ships can operate with as few as ten crew members. Including the captain, deck officers, and chief engineer, the total number of officers is often maintained below five.
Bulk Supramax Carriers
The majority of supramax ships navigate a course that is determined by supply and demand. For example, a ship that is transporting ore on its forward voyage can be returning with grain. These boats are not restricted based on the primary route they need to travel because they can pass through the majority of locks and canals.
It might be possible to bypass sailing across South America and instead use the Panama Canal to transit from the Atlantic to the Pacific Ocean. In a similar vein, a Supramax ship would bypass the Cape of Good Hope and instead go via Europe and Asia via the Suez Canal.
An additional crucial consideration when determining a ship’s itinerary is turnaround time. It’s common knowledge that bulk carriers take a long time to load and unload cargo. In contrast to container vessels, which can arrive at a port in as little as 12 hours, Supramax Cargo Vessels can require up to 60 hours. Although the duration does decrease somewhat when deck cranes are used, it is still regarded as one of the longest in the maritime sector.
The loading and unloading processes are crucial to the operation of any bulk vessel. These operations can be risky, especially for such vessels, as there is always a chance that the vessel will capsize or split in half. Many loading techniques can be used, depending on the kind of cargo. A sizable gantry bin or bucket is hung over each hatch entrance specifically for grain.
The bin’s bottom is hinged, allowing it to swing open and let go of its contents. The bucket returns to the pier to be reloaded after it is empty. Gantry and deck cranes are used to place freight inside the hold for various kinds of loads. Bulldozers that have been lowered into the holds are then used to arrange the cargo. Once properly positioned, the cargo is secured to prevent it from moving while at sea.
Let’s now examine the procedure for removing cargo from a Supramax Cargo Vessel. Cranes and additional machines are utilized in combination for this. Certain kinds of cargo can be lifted by cranes and then moved to the dock. There are conveyor belt systems available for other kinds of items. 500–700 tons of cargo can be transported using these belts in an hour. However, rates of up to 16,000 tons per hour are now possible because to advancements in shipping technology.
A self-discharging device with built-in conveyor belts is used by most ships. A ship that has been improperly unloaded may harm the ship as well as the dock. Cargo movement when the hold is only partially empty is a significant issue. The boat may topple over as a result of this.
Hospital Ships: Providing Medical Aid and Safety in International Conflicts
The vessel may even split in the middle if the load alternates between the fore and stern. Correct completion of ballasting is necessary to avoid this. Longitudinal bulkheads also lessen the possibility of shift.
The holds must be completely cleaned after the ship has been emptied. By doing this, pollution and corrosion of any kind are avoided. High strength water jets are typically employed for this purpose.
To sanitize the holds, chemicals are also dissolved in the water. The holds and bulkheads are so large that this procedure can take a long time. Nevertheless, there isn’t currently a substitute technology available to reduce the turnaround time.
Safety Concerns with Supramax Cargo Vessels
During the trip, load shifting is a problem for Supramax Cargo Vessels. This results in the Free Surface Effect (FSE), a hydrostatic issue. During a trip, when commodities migrate to one side, the center of gravity of the vessel is shifted away from the centerline.
This compels the ship to dangerously heel in one direction, which causes the ship to finally fill with water and capsize. In the late 1990s, this effect was the cause of multiple ship tragedies. Longitudinal bulkheads are incorporated into the vessel to lessen the relative severity of the FSE.
These are extra bulkheads to the transverse bulkheads that divide a ship’s holds. It is demonstrated that longitudinal separations diminish the FSE via an inverse square relation in the transverse direction. Transverse bulkheads aid in flooding management and are helpful in segmenting the holds into compartments. In the event that there is a problem with one specific hold, it also helps to prevent cross-contamination throughout the entire shipment load.
The structural integrity of the hull of Supramax Cargo Vessels is another significant issue. Single hull structures are frequently utilized in an effort to lighten the vessel, however they are unable to endure the combined impacts of torsion and corrosion. In a similar vein, flooding can occur from hatches that are not waterproof.
The last issue longer Supramax Cargo Vessels have is hogging and sagging, which quickly stretches the hull. Should there be a breach in the structural integrity, water could seep into a hold located at the front. The wall to the adjacent holds is under tremendous pressure as a result of the water’s accumulation.
This weakens the metal over time and could eventually cause a leak. Upon quickly filling the holds with water, the ship gradually loses buoyancy and descends. Safety precautions need to be considered at the design and operation stages in order to avoid this from occurring. Furthermore, as poor quality metals hasten the corrosion process, they should not be used.
