DISCOVER Magazine #7

Fleet renewal. Planning for the marine aggregate operations of tomorrow

Published in category: Dredging & Marine Contracting

Tough as old boats

The marine aggregate industry is operating some venerable dredgers. As Cemex UK Fleet Engineering Manager Mark Williams explains:

“Our youngest dredger is 20 years old. Our oldest 30. This is pretty representative of the industry as a whole, though, actually, our fleet is one of the youngest in operation in the UK.”

“Don’t get me wrong – these are tough machines, they can withstand years of operation in the harshest of environments. Our 30 year old dredgers are still going strong.”

Mark acknowledges, however, that there is a cut-off point, after which a new vessel starts to make sense.

“Eventually you reach a stage, beyond which a new dredger simply offers greater efficiency with increased production and reduced maintenance requirements; factors which make consideration of a new vessel attractive.”

Dredging in tomorrow’s world

There are other factors. To date, the aggregate industry has focused mainly on land-based extraction of resources, with marine activity contributing approximately just 15% of total operations. Land-based sites, however, have a relatively short lifespan – often between five and ten years. As such, many sites have become depleted. This, coupled with an improving economic outlook, is adding impetus to marine aggregate dredging as a solution.

With all this in mind, Cemex came up with a concept and went to market with a tender process. With the long lifespan of a marine aggregate dredger in mind, it was important not only to develop a vessel that could answer the needs of today, but also those of tomorrow. The result was the Damen MAD 3500.

Cemex and Damen contract signing MAD 3500

“From the tender process, Damen emerged as the perfect partner,” Mark states. “They took our ethos on board and rose to the challenge of building a vessel for the future. And, with all the concepts we wanted to incorporate, it was a challenge! But Damen embraced it wholeheartedly.”

Amongst the specific requirements that Cemex had, was that the vessel must be able to navigate the lock in Shoreham Harbour, from where it will operate.

For this, its length must not exceed 103.5 metres, with a deadweight of almost 7,000 tonnes and a speed under load of 12 knots. This translates into an additional 20% of aggregates per trip compared to the Sand Heron, the vessel the MAD will replace.

The Sand Heron, the vessel the MAD will replace

A dredger with depth

It is also crucial that the MAD be able to extract aggregate farther from shore than the predecessor vessel – to cover this requirement, the vessel will be able to operate at depths of up to 55 metres. “We are seeing a gradual increase in the need for extra depth – growing at around 3% per year. In order to ensure maintained relevancy for the future we went for a 30% increase in capability.”

The demands of the future, however, go way beyond simply increasing capabilities. “We wanted a vessel designed with safety as number one priority,” Mark says. “There are many examples of this philosophy throughout the vessel, but a good one is the engine room fire suppression system.

The standard, statutory requirement is for a CO2-based system. The danger with this is that application can pose a risk to anyone caught in the vicinity of the fire. What we have done instead is to select a NOVEC system. It’s a considerable investment, but safety is important to Cemex. “Similarly a lot of thought has gone into ergonomics. For example, the bridge layout is all about user-friendliness and there is a lot of space on board.”

These features contribute not only to safety, but also to making the vessel a comfortable place to work.

Comfort on board is very important to us. As ships become increasingly sophisticated we want to stay on top of this and ensure that Cemex remains an attractive place to work for our employees.

Naturally, when aiming at future-proofing a vessel, close attention to sustainability is also high on the list. The MAD’s credentials in this field are verified by the Classification society – the vessel will boast Lloyd’s Register’s ECO Notation – a voluntary accreditation that demonstrates standards in design, construction and operation that go beyond statutory requirements.

“The whole build process has been upgraded to ensure the MAD is everything you can expect from a modern, clean vessel. Sustainability runs throughout the vessel, it’s in its DNA. To give just a few examples, it has very quiet silencers, biodegradable oil in all the hydraulics and a highly efficient propulsion system to minimise fuel consumption and emissions.”

As if further benefits were needed, the MAD also offers cost-efficiency the Damen way – via reduced total cost of ownership. One of the challenges Cemex presented Damen was to develop a dredging system with no inboard pipework. Working with such abrasive materials, there is always the possibility that holes will appear in the pipework, increasing the risk of flooding. However, a system with no inboard piping has never been done on a vessel of this size before.

“With a lot of clever design from Damen Dredging Equipment we did it, considerably reducing the risk of flooding. This has implications way beyond the obvious improvements in safety – it has considerably reduced components requirements. And, where maintenance was previously a serious undertaking, it can now be conducted with just a on-board service crane, significantly lowering maintenance requirements and increasing uptime.”

The vessel is currently undergoing construction in Romania at Damen Shipyards Galati and is expected to be delivered Q4 2019 after which the last step will be for the MAD to make good on its promises.

We are looking forward to proving the operation of all this innovation,

concludes Mark.

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