OBJECTIVES OF TRIPOD
There is a need for fast ship transportation that is both efficient and
non-polluting. Conventional propellers are known to have a relatively low
efficiency. As an indicative example, most of ship propellers installed on
cargo vessels waste about 40 percent of the energy in the form of axial and
rotational losses in the wake, vortex generation, noise production,
cavitation, etc. The recovery of such losses is one of the major ways to
contribute to a more rational, environmentally friendly use of energy.
The main objective of the TRIPOD project is the development and validation of
a new propulsion concept for improved energy efficiency of ships. The ship
propulsion efficiency will be optimized through the advanced combination of
three existing propulsion technologies. In particular TRIPOD explores the
feasibility of a novel propulsion concept resulting from the integration of
two promising EU grown technologies (podded propulsion and tip loaded endplate
propellers) in combination with energy recovery based on counter-rotating
propeller (CRP) principle. The three existing technologies have been used
separately and are known to improve the overall ship propulsion efficiency as
compared to conventional propulsion. However, they have never been combined
together in a single propulsion package.
TRIPOD contemplates two types of propulsive innovations, which will be tested
for the first time:
The methodology of work involves on the one hand model tests and on the other
As a result of the investigation tools will be developed to assess the optimal
use of propulsive energy from environmental and economic viewpoints both for
new designs and for the retrofitting of existing ships with the novel
DEVELOPMENT OF TRIPOD PROJECT
Originally, the project was conceived for a scenario in which the entire
propulsion unit was to be redefined, called later new building scenario.
However, the ship-owner liked to know if a retrofit scenario would be
profitable in which not only the hull but also the original propeller was to
be maintained as part of the CRP unit. Then, during the first stages of the
project the retrofitting scenario was defined. Two alternatives were selected
with the aft POD propeller being either of conventional or CLT type. Then the
study cases were set for three different retrofit alternatives as follows: CLT
propeller alone instead of the original propeller, CRP case 1 with original
main propeller & conventional POD propeller, and CRP case 2 with original main
propeller & CLT POD propeller.
Finally, five model test programmes were established at two different ship
draughts dealing the first three with the retrofit scenario and the last two
with the new building scenario. In the new building scenario new propellers
were designed and tested on an improved ship hull.
In the last part of the project the real economic criteria applied by a market
leader are incorporated into the project. Elaborate procedures on how to
determine yearly fuel savings and emission reductions based on the vessels
operational profiles are applied and then the cost-benefit is assessed through
a TCO (total cost of ownership) analysis.