20 Anti-fouling: Affection and Efficiency
227
Suspended matter can produce substrates which are unsuitable for many types
of attachment [1] and may also interfere with livestock feed using water filtering.
Meanwhile, other pollutants can supply abundant nutrient and thus improve fouling.
Specifically, marine bacteria and aquatic species are less abundant in inland waters
compared to coastal waters. Another parameter influencing fouling severity is depth,
but it does not impact vessels because they are always floating on surface waters. Not
to mention, the interactions among the various species also alter the fouling cycle.
Bacteria can cause substantial mortality to their hosts in host-associated bio-film
because of degradation of the host tissue, and improve dragging of their hosts [4].
Additionally, bacteria can fight for nutrients, prevent exchange of gasses, obstruct
sunlight, and even promote that can inhibit attachment [2]. Other parameters depend
on the ship’s configuration, which can be a priori altered. For example, [14] notes
that fouling did not occur significantly at speeds greater above 6 kn [3].
Too low speed is inhibiting nutrient intake, while too fast flow rates increase shear
and turbulence which affect nutrient encapsulate of bio-films. According to [1], biofilm formation was swift and their viscosity increased in turbulent flows compared
with bio-films created under reduced flow circumstances. Thus, it can be added that
in this pattern a limit is expected, because higher speeds often entail higher levels of
bio-film detachment.
Unfortunately, the water flow from sailing speed cannot be changed to a large
degree, and depends on the type of ship. However, the design of the substratum,
which naturally impacts adhesion processes, relies on coating surface characteristics
and a coating can be optimized for anti-fouling purposes.
20.2.4 Algae as Organisms That Foul
Algae can settle and grow on a wide range of surfaces, both natural and man-made.
They are rapid colonizers and numerous species cannot compete with it. Marine
organisms on submerged man-made structures are responsible for major economic
costs and the recent recrudescence of algae in the environment has seen an increase
in the observed fouling phenomenon. The resistance penalty for ships is known to
increase by 11% in the presence of a light micro algal slime to 34% in the case of
macro algae colonization [5].
Marine organism colonization of immersed structures can cause significant
damage such as steel surface corrosion, reduced ship speed as a result of increased
drag [1]. Authors of [2] measured the effect of algal fouling on the hulls of ships and
found that the resistance penalty was increased by 11, 20, and 34% respectively, in
the presence of light slime, heavy slime, and macro algae, and increased production
of CO 2 , NO x , and SO 2 (related to increased fuel consumption).
227
Suspended matter can produce substrates which are unsuitable for many types
of attachment [1] and may also interfere with livestock feed using water filtering.
Meanwhile, other pollutants can supply abundant nutrient and thus improve fouling.
Specifically, marine bacteria and aquatic species are less abundant in inland waters
compared to coastal waters. Another parameter influencing fouling severity is depth,
but it does not impact vessels because they are always floating on surface waters. Not
to mention, the interactions among the various species also alter the fouling cycle.
Bacteria can cause substantial mortality to their hosts in host-associated bio-film
because of degradation of the host tissue, and improve dragging of their hosts [4].
Additionally, bacteria can fight for nutrients, prevent exchange of gasses, obstruct
sunlight, and even promote that can inhibit attachment [2]. Other parameters depend
on the ship’s configuration, which can be a priori altered. For example, [14] notes
that fouling did not occur significantly at speeds greater above 6 kn [3].
Too low speed is inhibiting nutrient intake, while too fast flow rates increase shear
and turbulence which affect nutrient encapsulate of bio-films. According to [1], biofilm formation was swift and their viscosity increased in turbulent flows compared
with bio-films created under reduced flow circumstances. Thus, it can be added that
in this pattern a limit is expected, because higher speeds often entail higher levels of
bio-film detachment.
Unfortunately, the water flow from sailing speed cannot be changed to a large
degree, and depends on the type of ship. However, the design of the substratum,
which naturally impacts adhesion processes, relies on coating surface characteristics
and a coating can be optimized for anti-fouling purposes.
20.2.4 Algae as Organisms That Foul
Algae can settle and grow on a wide range of surfaces, both natural and man-made.
They are rapid colonizers and numerous species cannot compete with it. Marine
organisms on submerged man-made structures are responsible for major economic
costs and the recent recrudescence of algae in the environment has seen an increase
in the observed fouling phenomenon. The resistance penalty for ships is known to
increase by 11% in the presence of a light micro algal slime to 34% in the case of
macro algae colonization [5].
Marine organism colonization of immersed structures can cause significant
damage such as steel surface corrosion, reduced ship speed as a result of increased
drag [1]. Authors of [2] measured the effect of algal fouling on the hulls of ships and
found that the resistance penalty was increased by 11, 20, and 34% respectively, in
the presence of light slime, heavy slime, and macro algae, and increased production
of CO 2 , NO x , and SO 2 (related to increased fuel consumption).