Matching Forces Applied in Underwater Hull Cleaning with Adhesion Strength of Marine Organisms

Abstract

Biofouling is detrimental to the hydrodynamic performance of ships. In spite of advances in hull coating technology, a ship must usually undergo underwater hull cleaning to remove biofouling during her in-service time. However, some cleaning practices may also lead to decreased lifetime of the fouling-control coating. Therefore, cleaning forces should be minimized, according to the adhesion strength of marine organisms present on the hull. In this article, values of adhesion strength found in available literature are discussed in the light of current knowledge on hull cleaning technology. Finally, the following knowledge gaps are identified: (1) data on adhesion strength of naturally-occurring biofouling communities are practically absent; (2) shear forces imparted by current cleaning devices on low-form fouling (microfouling) and corresponding effects on hull coatings are largely unknown. This knowledge would be valuable for both developers and users of cleaning technology.

Marine Biofilms: A Successful Microbial Strategy With Economic Implications

“…Nevertheless, hull cleaning usually has to be done at some point regardless of the fouling-control coating used on a ship. To avoid decreasing the lifetime of the coating, minimum cleaning forces should be applied, according to the adhesion strength of marine organisms attached to the hull (Oliveira and Granhag, 2016).…”

Design of surfaces for controlling hard and soft fouling

“…In fact, while the interfacial free energy difference between smooth surfaces of a high energy metal such as iron (2.4 J m −2 ) [22] and the lowest energy material C 20 F 42 (0.0067 J m −2 ) [23] is only a factor of 100, the modulus between a hard and soft surface can vary over as many as 5 orders of magnitude [24,25]. Thus, when bulk deformation occurs, [30][31][32] (obtained from CDC Public Health Image Library under public domain) and marine algae adhered to a ship hull [33], along with hard fouling materials like barnacles [34] (image reproduced with permission from [35], licensed under https://creativecommons.org/licenses/by/4.0/), clathrates in petroleum pipelines [36] (image reproduced from www.usgs.gov under public domain), ice on a wind turbine blade [37] reproduced from [38] (with licence under https:// creativecommons.org/licenses/by-nc-sa/3.0/) and inorganic scale deposited in a pipe carrying cooling water (licensed under https://creativecommons.org/licenses/by-sa/3.0/deed.en).…”

Towards an absolute scale for adhesion strength of ship hull microfouling

“…However, if cleaning events create damage, these may shorten the lifetime of the coatings, potentially resulting in a higher degree of biofouling (Malone 1980;Munk, Kane, and Yebra 2009). It is thus essential to gain knowledge on the forces required to remove early stages of fouling from ships' hull coatings, commonly referred to as the adhesion strength of microfouling (Oliveira and Granhag 2016).…”

“…Today, hull fouling is reduced using a combination of fouling-control coatings and in-water maintenance (Oliveira and Granhag 2016). Commercial fouling-control coatings are broadly grouped into two types: biocidecontaining antifouling coatings (AF), and non-toxic foulrelease coatings (FR), the latter exhibiting low surface adhesion properties (Yebra, Kiil, and Dam-Johansen 2004).…”

“…Hull grooming enables fuel savings and avoids increased emissions to the air from shipping (Hunsucker et al 2018). Also, hull grooming targets the early stages of marine fouling, ie microfouling, which typically requires lower cleaning forces than more advanced stages of fouling, ie macrofouling (Oliveira and Granhag 2016).…”