The performance of a ship can often be improved by retrofitting energy efficiency technologies. For full block vessels like tankers and bulk carriers, many retrofitting projects with PIDs (propulsion improving devices), eventually in combination with retrofitting an optimized propeller, have shown improvements of 5% in power demand and more.
Depending on ship type and size, and the targeted reference speed, numerous measures can be considered in principle:
- Retrofitting a bulbous bow optimized for the actual operational profile
- Retrofitting an optimized propeller
- Retrofitting propulsion improving devices (PIDs), e.g. stern ducts, wake equalizing ducts (WED), pre-swirl ducts (PSD), pre-swirl stators (PSS), vortex generator fins (VGF), propeller boss cap fins (PBCF), rudder bulbs in combination with propeller caps, twisted rudders, etc.
- Retrofitting air lubrication systems (ALS)
- Retrofitting wind-assisted propulsion systems (WAPS)
We align with renowned suppliers of such devices, assess the maturity of the device and the expected savings, evaluate the payback times for various scenarios, suggest packages for retrofitting and evaluate the outcome of the validation and verification model tests and/or the full-scale trials.
It is important to understand that these retrofit measures, which improve hydrodynamic performance, should ideally be undertaken only in combination with engine measures to ensure a suitable light running margin after conversion and still enable the ship to operate the engine at the minimum of the SFOC (specific fuel oil consumption) curve.
Typically, larger improvements in the EEXI can be expected when the retrofitting of energy efficiency technologies is performed in combination with a derating of the main engine.