All About Propulsion

De Graaf Aandrijvingen, Machinefabriek De Waal and Eefting Energy are all involved in the technical world of marine propulsion. One supplies power transmission components, the other manufactures and installs propulsion systems and the third delivers efficiency monitoring systems.

A lot can be said about propulsion. You can talk about propulsion systems, different kind of rudders, main and auxiliary engines, fuel consumption and reduction and more. Marine propulsion is what makes the industry move ahead. Maritime Holland spoke with the three companies about marine propulsion, special projects and trends that can be spotted in the industry.

Big, bigger, biggest “We supply the mechanical power transmission components for the shipbuilding and offshore industry”, explains Eddo Cammeraat, managing director of De Graaf Power Aandrijvingen, their activities in short. “Think of clutches, gearboxes, winches and slewing bearings, of which we can perform the engineering and take care of the sales. We are a small but flexible company, with a lot of technical knowledge that we use to serve our clients wishes, even when this means custom-made solutions. We mainly focus on components for bigger equipment, but the demands of the offshore and shipbuilding industry regarding a design are tremendous and grow each year.”

“I see this development in the entire industry”, continues Cammeraat. “Everything needs to be bigger and the boundaries of what is technically possible are pushed. This also has consequences for other aspects of the industry, for example regarding environmental laws and regulations.”

Marco de Waal from Machinefabriek De Waal shares this opinion:
“The environment continues to play an important role in the marine propulsion industry. While technical developments continue, the demands that are made regarding vessel design for example also keep on growing. Inherent to these developments is the fuel consumption, which is one of the first factors ship owners can and want to cut back on. For this cause, for example, hybrid propulsion systems have been developed and LNG has become a trend as an environmentally friendly and cost-effective fuel. We took a different path and looked at the resistance of a vessel and the savings that can be won by reducing the resistance a rudder creates.”

Flowing easily

Machinefabriek De Waal is located in the Beatrixhaven and Biesboschhaven in Werkendam, the Netherlands. Their activities contain three pointers: they manufacture their own products in the area of propulsion and transmission, like seals, shafts and rudders. They also have a repair and service department and lastly, they perform the completion of the building of a vessel. Although they started in the inland shipping industry, they are expanding their activities to seagoing vessels, the yachting industry and fishing industry. “1.5 years ago we contributed to a 79-metre long megayacht that was being built for a famous American. We delivered the pacific rudder, with the well-known NACA profile. Such prestigious projects are always nice to work on.”

De Waal continues: “In the inland shipping industry gasoil is the main source of fuel. We have developed a fuel-saving rudder for those vessels, the Easy Flow, which we also plan to bring to the sea shipping market this spring. In short we change the profile of the rudder, to reduce the resistance and let the water ‘flow easy’ along the rudder. Furthermore, they are a little bit longer than standard rudders and we set them further apart.” The Easy Flow was developed a year ago, as a result of demand from the market to reduce fuel consumption. Motor vessel Dolfijn was the first one to be fitted with the new type of rudders. “MARIN and the Delft University of Technology tested the rudder and the results were very good. In the meantime, already 25 vessels have been retrofitted with the rudder”, says De Waal.

Improve efficiency

Another possibility to reduce your fuel consumption is to monitor every move of your vessel’s propulsion systems. Groningen-based Eefting Energy delivers fuel and energy efficiency monitoring systems for the offshore and shipping industry. Harm Eefting, managing director of Eefting Energy, says: “Although the fuel prices are very low at the moment, which also reduces the necessity for companies to install monitoring systems, we still see a trend where ship owners decide to install the systems now. Perhaps this has something to do with the image companies want to carry out. Vessels that are proven to be more efficient have an advantage compared to vessels that are not.”

“The monitoring systems provide the crew with the necessary information to sail as efficient as possible”, Eefting continues. “On average our systems deliver a fuel reduction of six per cent. Furthermore, the data that are generated can be used to analyse the vessel’s performance, for example to analyse the service record, technical services but also the fuel consumption and costs. The shipping company can use these data to plan their trips more efficiently and to improve their vessel’s and equipment’s lifetime. When the crew is aware of the possibility to reduce fuel consumption by adapting their sailing behaviour and directly sees the results on the monitoring system, this can also lead to a reduction of fuel consumption.”

Modular systems

The monitoring systems in the engine room communicate with the systems on the bridge of the vessel. “A touch screen will be installed on the bridge, which displays the most important information to which the captain or the mate can react immediately if needed. The navigation equipment is also connected to the monitoring system, since these are parameters that influence the efficiency.The system is modular, so ship owners can decide which parts of their propulsion and auxiliary systems they want to monitor. Ship owners seem to be willing to measure more than just the fuel consumption of the main engines”, explains Eefting.

The growing demand for modular system is a trend, which is also recognised by Cammeraat: “Being able to provide modular systems has become a very important demand the last couple of years”, he says.  “Before, you had one unit that contained the whole coupling system. Nowadays, it is more a construction of Lego blocks. Clients want a system that is as compact as possible, but very flexible. They want to be able to, for example, switch between diesel power and electric propulsion without problems. We cooperate with Damen Shipyards on their hybrid tugboats. They are equipped with clutches from De Graaf, which are designed to disconnect the diesel propulsion systems and switch to electrical propulsion. In the meantime we are looking at thruster manufacturers to cooperate on developments in this area.”

The market demands

De Waal: “We noticed that the shipping industry and the current economy demand more modern equipment. Therefore, we designed and developed a new operating system last year, with which you can operate the weir machine on an iPad-like touchscreen. The inland shipping and yachting industry are leading in this trend, in the sea shipping industry people are more conservative. Decency, durability and low maintenance are very important requirements, which for example reduces the maintenance cycles since less maintenance is needed. This has a lot of advantages, for example on productivity and costs.”

Anne Kregting