Marine Maintenance Technology International - April 2016

HULL COATINGS (^) ⠿
MARINE MAINTENANCE TECHNOLOGY INTERNATIONAL | APRIL 2016 ⠿ 35
S
hip hull efficiency is a major part of
operating costs, and smoothness
of coatings accounts for a large
percentage of that. The talk two years
ago was around choices between competing
silicone-based ‘foul release’ hull coatings.
Although less discussed recently, hull
coatings are still a major consideration.
The world’s 50,000 ships consume 330
million metric tons of fuel per year. They also
create about 3% of the world’s greenhouse
gases. Depending on economic and energy
developments, the European Commission
estimates shipping emissions will increase
by an estimated 50% to 250% by 2050.
On average, over the five years of
operations between coating renewals, ship
speed losses averaged 5.9% compared with
freshly coated hulls. These statistics from
Jotun were based on data from 120 records
of dry dockings and for a variety of vessel
types using a range of hull coatings. A rule of
thumb suggests it takes a 3% increase in fuel
to compensate for a 1% loss of speed.
Most coatings manufacturers offer
calculations of prospective fuel savings from
their premium paints. It is clear that major
savings can be achieved but the industry
needs a commonly agreed measurement
method to enhance comparisons between the
hull coatings used on a particular ship. With
a market expected to reach US$10bn by 2018,
coatings competition will be intense.
Measuring performance makes good
financial sense for owners, as hull fouling
and poor propeller performance increases
energy and maintenance expense. Improving
this might reduce the world fleet’s annual
fuel costs by US$30bn.