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The Enemy Below - Adhesion and Friction of Ship Hull Fouling

Dinis Oliveira (Institutionen för mekanik och maritima vetenskaper, Maritima studier)
Gothenburg : Chalmers University of Technology, 2017.
[Licentiatavhandling]

Below the waterline, commercial ships are good targets for marine organisms to attach and proliferate, a problem commonly known as biofouling. A fouled hull means higher hydrodynamic resistance, which can result in significant fuel penalties. In a fossil-fuel thirsty maritime sector, this means disadvantages in economic, societal and environmental terms. This thesis presents tools for improving current practices related to hull performance management, focusing on the adhesion strength of marine organisms on different coatings (Paper I) and estimation of fouled-hull penalties (Paper II). In Paper I, knowledge gaps that hinder better matching of cleaning forces to adhesion strength of marine organisms are identified, and conclusions are derived from published adhesion strength data. From this adhesion-strength perspective, it is arguably better to invest in combating early stages of fouling, e.g. during idle periods, than using aggressive methods against advanced stages of fouling after an idle period. Regarding estimation of benefits of hull cleaning from a fuel-saving perspective, Paper II demonstrates that the hull form might be an important parameter to consider at low speeds and for less slender vessels. This thesis further applies a rapid calculation method (Granville method) in estimating the hull condition from vessel monitored data (noon reports). The estimated roughness height can be used as an indicator of the hull condition, with the advantage of being independent from vessel speed, which is not the case for other indicators, such as percentage speed loss.

Nyckelord: hull grooming, turbulent boundary layer, roughness, biofouling, frictional resistance, ship resistance, hull form factor, in-water hull cleaning, adhesion strength



Denna post skapades 2017-11-06. Senast ändrad 2017-11-10.
CPL Pubid: 252949

 

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Institutioner (Chalmers)

Institutionen för mekanik och maritima vetenskaper, Maritima studier

Ämnesområden

Energisystem

Chalmers infrastruktur

Relaterade publikationer

Inkluderade delarbeten:


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


Examination

Datum: 2017-12-01
Tid: 13:00
Lokal: Alfa, Saga-building, Hörselgången 4, Chalmers Campus Lindholmen
Opponent: Dr. Sverre Steen, Department of Marine Technology, Norwegian University of Science and Technology, Norway

Ingår i serie

Thesis for the degree of Licentiate - Department of Mechanics and Maritime Sciences 2017:11