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Paints and Coatings

hull
A

of a

difference

A
lthough fuel prices are dropping today, new The new AHR calculation builds on the landmark work

environmental legislation and pressure to improve of Dr Bob Townsin, the irst researcher and academic to
sustainability even further are still driving ship owners to establish the important link between hull roughness and ship

invest in more fuel-eficient vessels, enhance overall operational powering in the 1980s. His methodology was accepted by the
eficiency and reduce the total cost of vessel maintenance.International Towing Tank Conference (ITTC) in 1990 and the

Frictional resistance linked to hull roughness has always shipping industry continues to use it to estimate the AHR of a
been a major factor in determining ship eficiency and ways ship’s hull.

to reduce this have been explored at great length by many “While Townsin’s methodology is upheld by the shipping
coatings manufacturers.industry today, trends in hull coatings, ship yard practices,

In recognition of this, International Paint has come up with environmental changes and regulations , as well as vessel design
the irst major re-evaluation of average hull roughness (AHR) and operation have altered considerably over the past 30 years,”

prediction methodology in nearly 30 years to help predict more explained Philip Stenson, Technology Leader at International.

accurately the initial value and subsequent change in AHR over “Consequently, there is a real requirement for an
dry docking cycles.updated model that reflects the changing dynamics of the

The updated model is based on the collection, iltration and shipping industry.”
analysis of a dataset of 845 average hull roughness surveys He added: “Minimising hull roughness is a long-established

carried out between 2003 and 2014.and important objective for ship owners and operators

54 The SHIP Supplier 60th Anniversary Edition 1955-2015