The University of Gdansk, Poland published a paper quoting ABS figures for propulsion shaft failures and Offshore Supply Vessels and tugs amounted to 66 percent of the total failures in the report. Broken coupling flange bolts resulted in loss of propulsion, endangering the safety of the vessel. High torque values are generally considered to be a major cause of accelerated failure. Low speed operation and bad weather causes propeller loading to vary widely, shaft bending may take place as a result of ship hull deformation. The high torque loading when changing propeller rotation going ahead or astern, in some cases the torque may be doubled. Additional contributing factors may be: excessive wearing of intermediate bearings, accelerated stern bearing clearance growth and deteriorating engine mountings. CPP installations are less affected by this type of failure as the direction of rotation is constant..

Pollution exists in many forms and while cleaning up the air we breathe, is receiving the most attention from legislative bodies, the Marine Environmental Protection Committee (MEPC) of the IMO recently asked maritime nations to review their commercial fleets to identify the ships that contribute most to underwater noise pollution. DNV is showing leadership in creating a low noise notation for ships, “DNV Silent”. There are numerous civilian applications where low noise emission is desirable, such as research ships, fishing vessels and offshore support vessels. Main noise sources are propellers, diesel engines, gearboxes, generators, thrusters and water flow over the hull and making things worse, the ship’s hull acts as a sound box. Thinking about these issues early on in the ship specification allow many of these noise producing sources to be attenuated

An unusual craft looking like a small catamaran aircraft carrier took part in the Hamburg harbor’s 821st birthday celebrations. Launched in March 2010, PlanetSolar is the largest ship powered by solar energy in the world. Scheduled to complete a world cruise incorporating a circumnavigation during 2011, the entire 50,000km journey is to be completed only on solar power and is expected to take 140 days. The 85 ton displacement ship has a length of 31m and beam 15m and there is accommodation for around 40 guests. 537m2 of solar panels feed the largest lithium-ion battery in the world. Two 10kW electric motors, power a controllable pitch carbon fiber propeller. There is a small emergency diesel generator on board. Built by the Knierim Shipyard together with HDW in Kiel, Germany, the electrical management and control system is provided by Imtech, Germany.

Dr Herman Klein, of Germanischer Lloyd expressed his belief that the forthcoming IMO Tier 3 NOx rules will make the continued use of heavy fuel oil impractical, forcing commercial shipping fleets to switch permanently to distillate fuel from 2016. Using SCR catalysts is not an alternative as they quickly become clogged using HFO. Dual fuel HFO / distillate is impractical – hence his prediction of the demise of after 2016. A possible alternative is the Ecospec CSNOx system of exhaust gas scrubbing. A solution is passed through an exhaust scrubber to remove CO2, SO2 and NOx by absorption. Normal HFO can continue to be used, meeting the 0.1 per cent sulfur 2010 EU Directive, Tier 1 and 2 emission regulations and Tier 3 emission requirements.

The engine size for a ship is determined by the maximum power required but the amount of time spent at full power varies from most of the time to almost never. Probably the most extreme example of powerful engines hardly ever being used is in the world of tugs. In Wärtsilä’s latest Technical Journal, two new tug designs are shown together with a comprehensive insight into the operational usage profile of these vessels. Only four per cent of the time the engines are producing more than sixty per cent full power of which maximum power is around one per cent. In an example, an alternative to the twin 8L26 engined mechanical driven thrusters, is a hybrid solution where twin 9L20 engines are mechanically coupled to thrusters but also fitted with electric motors.

Global warming is shrinking the Arctic ice cap to such an extent that, according to some predictions, in only three years the Northern Sea Route, will be ice free in the summer enabling the Asia-Europe sea route over the top of Russia to be a reality. In 1932 a Soviet expedition was the first to successfully navigate the entire length of the route In 1987 the Northern Sea Route was officially opened up by Russia to international shipping. The Northern Sea Route is approximately 40 per cent shorter than the present route through Suez. Russia presently has a fleet of six powerful nuclear icebreakers with further construction planned.

In a cooperative development with Stop-Choc part of the Hutchinson Group, MTU the diesel engine manufacturer is offering a range of active engine mounts for some of their engine series. In the MTU system each of the four engine mounts consist of a vibration absorbing mount fixed to a solid box containing three vibration sensors and three force actuators, one for each axis. The inputs are fed to a control unit and using special control algorithms are analyzed and an appropriate signal is generated and fed back to the mount actuators resulting in a net decrease in noise and vibration.

Since the beginning of the year in the SECA emission control areas of Europe, only residual fuels with a maximum sulfur content of one per cent is permitted. On the West Coast of the United States a similar ban has been in force since July 1, 2009. The application of the new regulations is not without hazards. A higher number of propulsion failures directly associated with switching over from one fuel to another have been reported. Due to fuel temperature considerations, the changeover from one fuel to the other is not immediate but must be a gradually spread out over a period that can easily last from 30 to 60 minutes. Failure to do this gradually, could lead to seizure of the fuel pump due to low viscosity of the diesel fuel and thermal shock. This delay needs to be taken into account in the ship’s navigational planning of arrival or departure to ensure an orderly fuel change-over prior to entering the ECA. During changeover there is a danger of sludge formation, clogged fuel filters and separators, sticking fuel injection pumps and plugged fuel nozzles. Longer term effects if using a lubrication oil that is not matched to the fuel in use, can lead to cylinder liner lacquering on four-stroke engines with prolonged operation on low sulfur (mainly distillate) fuels causing expensive repair bills! Let’s hope that lessons are learned from the experience of others and these problems are avoided.