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2018 1
19th ICMCF The International Congress on Marine
Corrosion and Fouling
An investigation of marine biofilm effects on the roughness
and drag characteristics of surfaces coated with different
sized cuprous oxide particle
Chang Li1, Mehmet Atlar2, Maryam Haroutunian1, Colin Anderson3
1School of Engineering, Newcastle University, UK
2Ocean and Marine Engineering, University of Strathclyde, UK
3American Chemet Corporation, USA
JUNE 24-29, 2018, MELBOURNE, FLORIDA, USA
2018 2
• Frictional resistance may account for 25% to 80% of the
total ship resistance;
• Frictional resistance is directly affected by the surface
condition (e.g. coating, fouling etc.);
• An increase of 5 µm in roughness can lead to a 4%
increase in drag resistance;
• Slime (biofilm) fouling can cause 5%-25% increase in drag
penalties;
• Weed and hard shell fouling can result in at least 40%
increase in drag penalties.
Motivations
2018 3
D50=60μmD50=25μmD50=12μm D50=17μm
• Four different size of cuprous oxide were
selected with D50 (the median size) values of:
Coating preparations
• Binder system for tested antifouling
system was based on the VC17m part-B:
• Mix ratio: 3 (Cu2O):1 (VC17m/B), then sprayed
onto tested panels
• Dry film contains >90% of Cu2O (by weight)
2018 4
Cage tests
2018 5
Coating preparations
660mm
280m
m
600mm
220m
m
2018 6
Optical surface profilometer
PC Control
Unite
Advantages:
• Less damage, specially for
soft fouling organisms;
• Highly scanning accuracy;
• Easy access for various
surface conditions;
• Multiply parameters analysis
3D results plotting.
2018 7
Turbulent flow channel
PC Control
Unite
2018 8
Turbulent flow channel
2018 9
Fouling growth set-up
2018 10
Dynamic Deployment
• North Sea, Northeast England
• 0.3m submergence depth;
• 15% dynamic activities and
85% static conditions;
• Max. speed 22knots
• Temperature: 6.7°C to 15.3°C;
2018 11
Static Deployment
• Hanging 1.5m depth constantly;
• Temperature: 6.7°C;
2018 12
D50=12μm(Clean) D50=17μm(Clean) D50=25μm(Clean) D50=60μm(Clean)
D50=12μm(Fouled) D50=17μm(Fouled) D50=25μm(Fouled) D50=60μm(Fouled)
2018 13
SEM
D50=12μm(Clean) D50=12μm(1.5M)
D50=12μm(4.5M)
With biofilm present
• Surface fully covered with biofilm;
• No individual Cu2O particle can be
recognised;
• Surface microstructure profile has
completely been reformed;
• Surface profile became rougher;
2018 14
D50=17μm(Clean) D50=17μm(1.5M)
D50=17μm(4.5M)
With biofilm present
• Surface fully covered with biofilm;
• No individual Cu2O particle can be
recognised;
• Surface microstructure profile has
completely been reformed;
• Surface profile became rougher;
2018 15
D50=25μm(Clean) D50=25μm(1.5M)
1.5-month
• Mixture of Biofilm and Bacterial
colonies are largely appeared;
• Most of Cu2O particles have been
covered;
2018 16
D50=25μm(Clean) D50=25μm(1.5M)
4.5-month
• Top surface are fully covered with
biofilm
• Microstructure profile has been
obviously changed;
D50=25μm(4.5M)
2018 17
D50=60μm(Clean) D50=60μm(1.5M)
1.5-month
• Bacterial colonies are largely
appeared and settle on the surface;
• Microstructure profile changes very
slightly;
2018 18
D50=60μm(Clean) D50=60μm(1.5M)
D50=60μm(4.5M)
4.5-month
• Cu2O particles were covered with
biofilm
• Microstructure profile has been
obviously varied;
2018 19
Frictional Drag Measurement
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
Clean 1.5M 3M 4.5M 6M
Panels Condition
C12 C17 C25 C60
(%)
2018 20
Frictional Drag Measurement
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
Clean 1.5M 3M 4.5M 6M
Panels Condition
C12 C17 C25 C60
(%)
2018 21
Summary: Roughness Analyses
• Cuprous oxide can efficiently prevent hard shell fouling rather
than biofilm fouling;
• Turbulent flow channel can provide a very straight forward access
to evaluate the friction drag of different coatings;
• Biofilm can shortly generate and develop on the relative smoother
surface (or with lower microstructure profiles i.e. D50=12µm,
17µm);
• The interaction between biofilm and surface characteristics
(particle size) would take biofilm longer time to fully develop over
a rougher surface (i.e. D50=60µm);
2018 22
NICE SHAVING!!
2018 23
19th ICMCF The International Congress on Marine
Corrosion and Fouling
Thanks for listening
Questions?