Caterpillar Marine is collaborating with Sanmar Shipyards in Istanbul, Turkey to build an innovative tugboat with a hydraulic hybrid propulsion system. Sanmar is the largest tug builder in Turkey with over 40 years of experience and known as a market leader at the forefront of the tug building industry.
The Cat Marine Advanced Variable Drive (AVD) is a patented system leveraging Caterpillar’s extensive experience with heavy-duty continuously variable transmission (CVT) technology, advanced controls and power system integration knowledge. The AVD system provides significant improvements in both fuel efficiency and vessel performance through a fully integrated hydro-mechanical propulsion system.
Different from a typical Power Take In (PTI) solution, the AVD incorporates a planetary gear set allowing seamless clutch engagement of main engines, auxiliary engines, or both to provide a scalable power installation to meet any customer need in terms of maximum vessel speed, power, or bollard pull.
This also allows propeller speed independent of engine speed so optimal engine efficiency can be achieved leading to fuel savings of fifteen to twenty percent. Basically, all the benefits of a variable speed Diesel Electric Propulsion (DEP) system at a fraction of the cost and size.—Nathan Kelly, Caterpillar Marine Product Definition Engineer
The AVD system is also flexible and can accommodate multiple configurations. Auxiliary engines can be utilized to accommodate low load or transit operations greatly extending time to overhaul and reducing service costs on main engines. Electric motors can also be used instead of hydraulics if required.
AVD enables straight forward integration of either diesel, natural gas or gas turbine engines or any combination of these as prime movers, accommodating various levels of engine load acceptance capability and engine speed regimes. Main engines can be downsized in most applications with supplemental power provided by auxiliary engines. The system provides inherently high levels of propulsion redundancy. It is fully scalable to meet requirements of a wide range of vessel types, applications, and power levels.—Igor Strashny, Caterpillar Innovation and Technology Development Engineering Manager with responsibility for Advanced Marine Propulsion
The Sanmar hydraulic hybrid tug will be a Robert Allan Ltd. designed RAmparts 2400SX harbor tug incorporating an integrated Caterpillar AVD system of 3512 main engines, a C32 auxiliary engine, Caterpillar MTA 627 fixed pitch tug thrusters, and bridge controls. It will carry Fifi 1 designation with 70T metric bollard pull and will be supported by Turkish Caterpillar dealer Borusan Makina.
The AVD system will also include a fully integrated controls system with customizable operating modes and display panels at the bridge. Compared to a conventional tug with equivalent bollard pull, the Return on Investment (ROI) is estimated at 3 years or less based on projected fuel and operating cost savings.