Page 18 - 2024 - Q3 - Minerva in Focus

Bulk Carriers A look into Minerva’s Newbuildings

A defining feature of Ultramax bulk carriers is the presence
of onboard cranes and grabs, which allow for self-loading
and unloading, making these vessels versatile in both large
and small ports.

What is an Ultramax bulk carrier?
An Ultramax bulk carrier is larger than a Supramax carrier but
smaller than a Panamax or Capesize vessel. Though “Ultra-
max” is not an official classification, it typically refers to bulk
carriers ranging from 60,000 to 65,000 DWT. These ships
are widely employed in the transport of a variety of dry bulk
commodities such as coal, grain, ores, and cement. Equipped
with onboard cranes, Ultramax vessels can operate inde-
pendently of port equipment, which is essential for loading
and discharging in regions with minimal port infrastructure.
Cranes and their importance in bulk handling
The onboard cranes of Ultramax vessels form a vital link in
the distribution chain of raw materials, ensuring efficient cargo
transfer from vessels to barges, trucks, or storage facilities.
These cranes are often used in conjunction with grabs – at-
tachments that allow them to handle bulk materials like coal,
Achieving flexibility: grain, and ore. This onboard equipment significantly enhances
the ship’s versatility, reducing dependence on shore-side
The use of cranes infrastructure and enabling faster cargo operations.

and grabs in Minerva's Types of grabs and their applications
Grabs are attachments that enable cranes to efficiently handle
Ultramax bulk carrier a wide range of bulk materials. The most common types of
grabs used in Ultramax vessels include clamshell grabs and
newbuildings shell (or orange peel) grabs:
Clamshell Grabs are used primarily for handling
•
free-flowing bulk materials such as coal, grain, and
sand. These grabs consist of two hinged buckets that
by Capt. Efstathios Kourtis, scoop up material, making them ideal for large-vol-
Head of Marine, Minerva Dry Inc. - ume operations.
HSQ Marine Department • Shell Grabs (Orange Peel Grabs) are typically used for
handling irregularly shaped items like scrap metal or
rocks. These grabs have multiple “fingers” or “jaws”
and are designed to grip and lift difficult-to-handle
cargoes.

Grabs can be further categorised into mechanical, hydraulic,
and electric ones, based on their operating mechanisms:
• Mechanical Grabs rely on cables from the crane to
operate the opening and closing mechanism.
• Hydraulic Grabs use hydraulic systems to open and
Ultramax bulk carriers play • close the jaws, allowing for more precise control.
Electric Grabs are powered by an electric motor,
a crucial role in the global offering even more control and efficiency.
transport of dry bulk cargo. Considerations when selecting a grab
These vessels, which sit When selecting a grab, operators must ensure that the total
between Handysize and Panamax weight of the grab and its cargo does not exceed the crane’s
bulk carriers in terms of safe working load (SWL). Additionally, the properties of the
size, offer flexibility for material being handled, such as its density, moisture content,
operations in ports with limited and flow characteristics, play a crucial role in grab selection.
For example, dense materials like manganese ore may re-
infrastructure while carrying quire grabs with teeth to penetrate compacted cargo, while
significant cargo volumes. lighter materials like grain may necessitate self-sealing grabs
to prevent spillage.

18 ISSUE 29 / Q3 2024