On Optimization of Underwater Hull Cleaning for Greater Fuel Economy

Abstract

In addition. he is u member of SNAME, the Nutiorial Associatioii of Corrosiori Engineers, arid the Electrochemical Society. Mr. Preiser has written extensively in the techriical literature and holds 25 U.S. Patents 011 various corrosion arid fouling control methods arid devices. Mr. Donald R. Laster received his B.S. degree in Physics f r o m the Uiiiversity of South Carolilia in 1960 arid his M.S. degree iri Physics from the Drexel Institute of Technology in 1968. He has beeri employed at the David W. Taylor Naval Ship R & D Center since 1960 working in sensitig systems applications and techt~ology such us tionacoustic A S W. ship performance measurement. arid fuel use ariulysis. A member of ASNE sime 1980. he ulso is a member of IEEE arid Sigma Pi Sigma. ABSTRACTThe rapidly increasing cost and the uncertain supply of oil provide strong impetus to find ways to conserve ships' fuel and to optimize its use. Underwater mechanical removal of marine fouling from U.S. Navy ship hulls and propellers has been shown to result in immediate and rather substantial fuel savings. The long-term savings from underwater cleaning is not nearly so certain because of the interactions between the cleaning techniques, paint performance, and regrowth of the fouling. Of particular interest is the sensitivity of the fuel savings as a function of cleaning frequency.The following three questions are addressed: Does underwater cleaning lengthen Anti-Fouling (AF)Does underwater cleaning really save fuel? Is underwater cleaning cost effective?The answers to these questions obviously depend strongly upon the use of the ships and the manner in which they are operated. For U.S. Navy ships, underwater hull cleaning will save fuel provided adequate attention is given to the scheduling of the cleaning in terms of drydock cycle and deployment. Additional efforts toward optimization of underwater cleaning also are discussed. paint service life?

In-Water Cleaning and Capture to Remove Ship Biofouling: An Initial Evaluation of Efficacy and Environmental Safety

“…It is also important to note that most existing in-water cleaning systems have been developed to specifically address vessel operations and fuel consumption, and without a debris capture process (Jones, 1999;Preiser and Laster, 2009). Therefore, most current in-water cleaning systems are focused exclusively on removing biofouling from the main hull surfaces to reduce drag, while ignoring ship niche areas (e.g., sea chests, thrusters and rudders), which can be "hot spots" for the transport of non-indigenous biofouling species (Coutts and Taylor, 2004;Davidson et al, 2009;Moser et al, 2017).…”

Grooming using rotating brushes as a proactive method to control ship hull fouling

“…Ship hull cleaning methods are typically aggressive, may shorten the lifetime of the coating, and only partially aid in reducing drag, since the cleaning is not performed until fouling is well established (Preiser & Laster 1981). Cleaning may also increase the amount of biocide released.…”