Back to the Future

It’s déjà vu all over again as companies innovate to meet strict environmental standards.

By Chad Fuhrmann

Today’s maritime industry is driven by the traditional power plant first developed over a century ago.  Despite many advances, the modern iteration of Rudolf Diesel’s eponymous engine still has a peak efficiency of only fifty percent. Its inherent limitations mean that further reductions in fuel consumption and emissions simply cannot be achieved by the engine itself. Industry stakeholders therefore continually seek improvement through innovative technological advances in both engines and propulsors.

                  Enhanced component design and construction allow individual engines, such as Wärtsilä’s technologically advanced 46F, to achieve efficiencies exceeding fifty percent. However, it is integration technology, such as fuel-switching capabilities, that provide 46F users with exceptional fuel economy and outstanding power ratios.

                  MAN Diesel & Turbo’s G-type series likewise incorporates improvements in individual engine designs and the integration between a vessel’s propeller and engine. The G-series engine incorporates an ultra-long stroke that reduces engine speed for large propeller optimization. For the offshore sector, MAN developed a new twelve-cylinder 175D engine optimized for offshore supply vessels working under strict environmental regulations. The 175D is equipped with a modular exhaust treatment system based on the company’s MAN Ad Blue technology that satisfies IMO Tier 3 requirements.

Dual-Fuel Concept

The dual-fuel concept utilizing marine gas oil (MGO) and liquefied natural gas (LNG) is hardly new as Rudolf Diesel’s engines were capable of running on a variety of fuels as well. But revisiting this old idea with new capabilities promises to greatly improve engine efficiency while reducing toxic emissions in “gas mode.”

                  Caterpillar’s Marine Division has been capitalizing on almost a century’s worth of experience with engines to position itself as an industry leader in the development of dual-fuel engine technology.  The company delivered its first dual-fuel MaK M 46 DF engine in 2013, offering the flexibility of using heavy fuel oil (HFO), MGO or LNG to operate vessels in all geographical areas and in compliance with IMO 3 as well as EPA Tier 4 regulations.

                  The M 46 can also be retrofitted onto existing M 43 C power plants. One such project is the in-hull retrofit of the Fure West tanker (owned by Furetank Rederi A/B), including an integrated CAT LNG gas system.

Propulsors

At the other end of the spectrum are the propulsors driving the industry’s platforms, an area rife with innovation. Thruster manufacturer Schottel’s work with high-torque gearing, for example, has resulted in increased torque ratings across its portfolio of propulsion units including azimuthing thrusters such as the SRP Rudderpropeller, the SCD Combi Drive (azi-pull/azi-thrust) combination and the SPJ Pump-Jet.

                  Schottel is also a leader in rimdrive propulsion, offering its SRT line of rimdrive thrusters that compete with propulsion manufacturer Voith and its Voith Inline Propeller (VIP) and Voith Inline Thruster (VIP) series. Each of these propulsors foregoes the traditional gearbox and motor coupling by integrating the two within the thruster itself. The result is a permanent-magnet electric motor driving a propeller without needing an axle, shaft or gearing – or the friction losses that accompany them. The design itself is not only efficient but also increases the amount of usable space within the vessel.

                  Perhaps one of the most fascinating alternatives to conventional propulsors is the cycloidal propeller developed and patented by Voith. The Voith Schneider Propeller (VSP) is comprised of a circular disk with controllable blades extending at a 90-degree vertical angle below a vessel’s hull. The angle of the blade determines the direction of thrust, and the magnitude is determined by the rotational speed of the disk, both of which are completely controllable.

                  Developed nearly a century ago, this strikingly simple mechanism is in use all over the world, primarily in tugboat applications. Although it has only recently seen wider application in the marine industry, its reliability, power capabilities and unique stability benefits may provide even greater opportunities for it in the offshore sector.

                  Waterjets offer another compelling option for the industry. With peak operating efficiencies well above conventional propellers, their power, precise control and reliability make them attractive options for specific offshore applications such as crewboats. Unique offerings such as HamiltonJet’s JETanchor positioning system offer operators the advantages of automatic control. Combined with their low underwater profile and consistent power absorption, waterjet propulsion may see application in more varied circumstances, especially given the increasing attraction of dynamic positioning technology.

Impact of Government Regulations

The desire for cost savings plays a key role in all of these advances, but the primary driver is undoubtedly government mandate. Industry leaders are driven by the increasingly complex web of requirements to supply the most economical power, propulsion and design integration solutions to their clients.

                  Rather than struggling to comply with rapidly changing requirements, many industry leaders are finding it far more cost-effective to proactively set the standard. For example, Harvey Gulf’s Harvey Energy and her sister vessels are equipped with Wärtsilä’s dual-fuel technology and designed to comply with the strictest environmental standards. Not surprisingly, they are touted as the cleanest vessels in the Gulf of Mexico, and they are the first vessels to carry a brand new class notation – the “ENVIRO+, Green Passport” Certification from the American Bureau of Shipping.

                  Similarly, Caterpillar and Harley Marine Services first teamed up almost five years ago to upgrade three tugboats after the company elected to install the 3500-series emissions kits on the Caterpillar 3516B marine engines. In the process, each of the vessels upgraded from EPA Tier 0 to Tier 2 and witnessed a noticeable improvement in efficiency. More recently, the two organizations again collaborated on Harley Marine’s newbuild line haul boat, Earl W. Redd. Citing the success of the Tier 2 upgrades, the company selected the 3516E engine, the first Caterpillar Marine engine solution meeting EPA Tier 4 final emissions standards coming into effect this year.

                  By taking the lead in adopting new designs and integrated technology solutions, maritime stakeholders can reap the benefits of the industry’s comparatively limited environmental impact and realize increased profits as well.  – MarEx

Chad Fuhrmann is Business Director, Americas for Maritime Assurance & Consulting Ltd. This is his first appearance in the magazine.