Cutter power of 12,000 kW

The cutter head, equipped with interchangeable cutter teeth, transfers the available cutter power into the seabed to break up the soil and rock. Given the unprecedented cutter power of 12,000 kW, a new scale of cutter heads and teeth had to be developed to be able to withstand these significant forces. Requiring more strength and wear length, the individual teeth are huge and weigh more than ~45 kg per piece. Furthermore, a set of dedicated rock cutter heads was designed to be able to cut even the strongest rock formations.

The industry's heaviest cutter ladder

CSD Spartacus' cutter ladder weighs 2,550 metric tonnes, significantly more than any other cutter suction dredger currently active in the world. This hefty weight means that sufficient ground pressure can be exerted, allowing Spartacus to take more rock at a time without the cutter head being pushed out of the rock. The size of the ladder allows for dredging depths up to 45 metres, without any extensions required. Again, this is world-leading compared to its peers.

Integrity of the dredger

To ensure the integrity of Spartacus over its full lifetime, the vessel is equipped with sensors linked to an operational monitoring tool. This tool monitors the dredging-induced vibrations and allows the dredge operator to stay below structural alarm levels. By continuous monitoring, potential damage such as cracks in the cutter ladder can be prevented or detected at an early stage.

Workability safely pushed to the limits

Spartacus' 73-metre-long spud can provide up to twice the holding capacity compared to the spuds of the previous generation of mega dredgers. The main spud is based in a fully flexible spud carrier. Spud loads are measured, which, in combination with a dedicated forecasting and modelling tool, enables the crew to push the limits of the vessel’s workability, without risking damage the vessel or its components.

One of DEME’s most important strategic priorities is to become climate neutral by 2050. This aim was a major consideration when designing Spartacus and has been achieved by the implementation of both fuel-saving technologies and a new generation of marine engines capable of using the fuels of the future with very low or zero greenhouse gas emissions.

Reduction in fuel consumption and emissions

The four main generators, with a power output of more than 10,000 kW each, are capable of running on traditional marine fuel types and Liquefied Natural Gas (LNG). CSD Spartacus is equipped with three diesel-electrically driven pumps, totalling 25,500 kW of pump power. The diesel-electrical drives, in combination with a fully flexible layout, allow for an optimised and tailor-made consumption of pump power in relation to the soil characteristics, discharge length and discharge height, further contributing to a reduction in fuel consumption and emissions. Additionally, pipelines on board – with a diameter of 1,200 mm – allow transport of large quantities of mixture and material while minimising losses.

Spartacus is also equipped with several other energy-saving technologies such as a cold recovery system to drive the air conditioning. By cooling water using the evaporation of the LNG, which is stored at -160 degrees Celsius, up to 400 kW of electrical power can be recuperated.

In another world first in dredging, Spartacus is equipped with a waste heat recovery system. This uses waste heat in the exhaust gases of the main engines to recuperate energy otherwise lost to the environment. Depending on the power output of the main generators’ engines, up to 2,000 kW of power can be recuperated.

Project spotlight: Abu Qir, Egypt

Spartacus' advanced capabilities to reduce emissions per cubic metre dredged, while at the same time optimising workability, are demonstrated by its maiden project in Abu Qir, Egypt. And indeed, this huge land reclamation and dredging project also highlights Spartacus' superior performance compared to the previous generation of mega CSDs.

In Abu Qir, DEME’s diesel-direct driven cutter suction dredgers were working alongside CSD Spartacus to reclaim land for a new deepwater port. Both vessels worked on similar discharge layouts of approximately 2.3 kilometres and operated in cutting limited mode, each applying its maximum available cutter power.

Under these-like-for like conditions, the CSDs from the previous generation required approximately 38 MJ of energy per cubic metre of transported in situ material. However, Spartacus, operating on a combination of LNG and marine gas oil, required only 22.4 MJ per cubic metre.

GHG reduction of more than 40%

Expressed in greenhouse gas emissions, this corresponds to a reduction from around 2.9 kg CO2 equivalent per cubic metre to 1.7 kg CO2 equivalent per cubic metre – a substantial improvement of approximately 41% per unit of dredged material.

This reduction reflects the combined effect of increased cutter power and cut geometry, larger discharge diameters reducing hydraulic losses, optimised power deployment across pumps and generators, and additional energy recovered via waste heat and cold recovery systems.

In addition to improved efficiency, the Abu Qir project confirmed Spartacus' enhanced workability. The scope included both sheltered basin areas and an unsheltered borrow area exposed to the Mediterranean Sea. Proving DEME’s design choices, Abu Qir demonstrated Spartacus' unrivalled workability in unsheltered conditions with up to and over 300% of the maximum wave height at a given period. Spartacus could continue in conditions far exceeding the typical limits of earlier mega cutter suction dredgers, resulting in extended workable weather windows. During the project, dredging was successfully carried out at depths of up to 44 metres, a world record for CSDs.

Cutting hard rock in Leixões

Where the Abu Qir assignment provided valuable data on cutting and discharge productions, as well as workability in unsheltered conditions, the first real test for CSD Spartacus' advanced cutting arrangement came during its second project: dredging 1.7 million cubic metres of hard rock in a port deepening programme in Leixões, Porto, Portugal.

The geology is heterogeneous and includes schist, migmatite, gneiss, very strong granite and orthogneiss. Surveys confirmed the presence of intact rock with limited fracturing - conditions traditionally considered unfavourable for cutter suction dredging.

Following removal of the overlying sediments by trailing suction hopper dredgers, Spartacus was tasked with tackling the hardest rock. Despite the strength and integrity of the material, the project was completed on schedule and production levels achieved exceeded what was previously regarded as economically viable for cutter suction dredging.

Advanced drive train design and continuous monitoring enabled sustained high power cutting without structural damage, crucially demonstrating that strong, intact rock can be dredged economically without resorting to drill-and-blast methods.

Removal of rock at Tanger Med

At Mount Cires, located near the port of Tanger Med, the dredging challenge revolved around a relatively compact but technically demanding scope of work. The task involved cutting into the bedrock to carve out a 15-degree inclined addition to the port’s existing access channel, effectively extending its footprint. This required precision in execution, as the area comprised intercalated layers of claystone, limestone and sandstone, with notable differences in erosion resistance between ridges and troughs.

Despite the geological complexity and the structural variability of the bedrock, Spartacus managed to perform the dredging operations within a remarkably short timeframe, in just seven days. The time-critical project further underlined Spartacus’ cutting capability and effectiveness in delivering high-quality results in geologically sensitive conditions.

A new era for hard rock dredging

Data collected from the Leixões and Mont Cires projects offer clear and compelling evidence of a fundamental shift in the feasibility of dredging hard rock using CSD technology. These projects demonstrate that with the right vessel and strategic execution, even the most demanding geological formations can be tackled effectively – both from a technological and economic perspective.

When reviewing past hard rock dredging projects carried out using the previous generation of mega CSDs, a pattern becomes clear: traditionally, strong and intact rock formations mark the point at which productivity declined sharply, often falling to levels that rendered operations inefficient and cost prohibitive. Drill-and-blast then became the default solution, despite the downsides in terms of environmental impact and operational complexity.

The performance of SMCSD Spartacus has decisively altered this balance. In Leixões, Spartacus was pushed to the limits of its design capabilities while operating in orthogneiss rocks, a type previously considered beyond the viable reach of cutter suction dredging.

Unrivalled production rates

However, DEME’s Smart Mega CSD successfully removed 1.7 million cubic metres of rock in just six months. Spartacus delivered production rates previously unseen in such geological conditions, thereby marking the first time a project of this complexity and scale has been completed economically using a CSD.

This important step for the industry is not solely about power and production volume. It has important implications for sustainable infrastructure development: fewer explosives, reduced vibration impacts, improved dredging accuracy and lower emissions per cubic metre of material moved.

The ability to carry out these works reliably and without incurring structural damage to the dredger itself, underscores the technological sophistication of Spartacus. The advanced cutting arrangement and real-time structural monitoring systems enabled safe, yet aggressive, operations in difficult conditions. By continuously tracking vibration levels and structural integrity, operators are empowered to manage the vessel within comfortable operational limits, ensuring longevity, reliability and while maintaining equipment integrity throughout the campaign.

These projects act as proof-of-concept case studies that redefine the upper limits of what is feasible using cutter suction dredgers. Spartacus' performance indicates a paradigm shift, where very strong, high-integrity rock can now be dredged economically and effectively without defaulting to drill-and-blast techniques.

Ultimately, these early projects signal a new era in hard rock dredging – one where previously prohibitive conditions can be met with confidence and efficiency. Spartacus is redefining the industry standard for what is technically and economically achievable in modern dredging and DEME is once again pushing the boundaries of what is possible.