Propeller and Propulsion System Optimisation
The quest for reduced fuel consumption, emissions and noise levels!
Model test races
- As a system supplier for the merchant, naval and offshore markets Kongsberg is often attending comparative performance races where several suppliers are competing for the order. The supplier with the best “performance” normally wins the contract to deliver propulsion equipment to the vessel in question. These races are being made at model scale in a towing tank, normally at a well reputed test institute. Comparison of power consumption over a speed range is compared in a self-propulsion test where a self-driven hull model is run in a towing tank while thrust, torque and shaft speed of the propeller(s) are measured. The supplier with the lowest power consumption, hence the lowest fuel consumption becomes the “winner” and have a chance to get the contract to deliver the requested equipment.
- The competitive situation, especially in the merchant market has changed over the last 10 years from being a question only about investment cost to a situation where efficiency and fuel consumption are playing a more important role in the selection of supplier. This is a better situation than just the price of the equipment being the competing parameter and of course comes with environmental awareness and regulations on emissions.
Underwater Radiated Noise – an environmental issue
- The current trend is that underwater radiated noise (URN) levels are becoming more and more important. Due to the rise in shipping on the seas and operations increasing also in environmentally sensitive areas, noise pollution in the sea is becoming an increasingly important issue. More frequently, operators (offshore and cruise) request documentation of hydro acoustic noise emissions from ships/propellers when they operate in ocean areas with a high population of certain marine mammals (whales, seals, dolphins, walruses etc,). In 2010 DNV published the first class notations on underwater radiated noise as a response to environmental concerns on underwater noise pollution.
A better way of comparing performance
- Kongsberg very often comes out as a winner in these model test races, but a better way of optimising propulsion and reducing fuel consumption of a new vessel is to involve a supplier of propulsion systems such as Kongsberg at a much earlier stage of the project. Kongsberg have World Class propulsion expertise and the capability to do optimisation of the aft ship, interaction effects, propeller and the drive train and in cooperation with ship yards/owners strive for an iterative development of the propulsion system with a life-cycle perspective.