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TECHNOLOGY ROADMAP: TRANSPORTATION

In addition to this, there is fuel consumption for ratio are the most important non-dimensional
operation of auxiliary engines that supplies power main parameters, which influence the form
to the auxiliary machineries and to the lighting related wave-making resistance of a ship.
loads. Ships other than the case shown will have Studies have shown that based on the typical
similar type of losses, although, the percentages ship design standard today, the EEDI may
may differ. be decreased by 5-10% by selecting more
favourable hull proportions (i.e. a lower
It can be clearly deduced from the above block coefficient and a higher slenderness
analysis that most important causes for energy ratio), even without changing the speed or
consumption on board a ship are due to introducing any new technical measure. Thus
hydrodynamic effects, which comprise of energy optimization of hull dimensions and form
spent for propulsion and in overcoming ship’s are important and crucial for ship energy
resistance (inclusive of wave-making resistance efficiency.
and hull friction i.e. viscous drag). Other than for
passenger ships where hotel loads and other FIG 4.2: OPTIMIZED HULL DIMENSIONS AND
auxiliary systems are large contributors, cargo FORM[2]
ships use up to 90% of all practically available
energy for propulsion, excluding all internal losses
in a combustion engine.

Consequently, a focus on low ship resistance
and improved propulsive efficiency through
hydrodynamic optimization, promises the largest
gain. Besides this, optimization of energy systems
together with use of promising technologies for
energy generation from alternative fuels or non-
fossil renewable sources on-board a ship lead the
way ahead for future low energy and low emission
i.e. green shipping.

4.2 TECHNOLOGIES WITH POTENTIAL FOR
ENERGY SAVING/ EMISSION REDUCTION
Technology options in respect of above
mentioned aspects that are technically achievable
from an engineering point of view and have the
potential to significantly improve energy efficiency
and reduce emissions from ships in the short,
medium and long term are discussed below:

4.2.I. Hull and propeller
A ship’s hull and propeller design contributes
significantly to her overall hydrodynamic efficiency. (b) Hull Coating: Apart from wave-making
Discussed below are the measures that have the resistance, viscous drag plays a very important
potential for improvement of hull and propeller role in overall hydrodynamic efficiency of a
efficiency through hydrodynamic optimization: ship. The main parameter affecting viscous
drag of a ship is surface roughness of its hull.
(a) Optimized hull dimensions and form: Major The energy spent in overcoming viscous
Hull dimensions of a ship are determined drag of a ship can be significantly reduced by
at the design stage (Fig 4.2). Careful hull enhancing the smoothness of hull through
design can significantly reduce the energy initial production quality, surface preparation
spent towards wave resistance of a ship. The and maintaining it free of fouling during vessel’s
hull dimensions should meet the specific operation using advanced hull coatings. Such
requirements of the ship such as the shipping low-surface energy (LSE) coatings create non-
routes (port and canal restrictions), the type stick surfaces similar to those known in Teflon
of ship, the deadweight tonnage and the ship coated pans. By reducing the hull roughness
speed. The block coefficient and slenderness and inhibiting marine fouling, LSE coatings have

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