Measuring predictors of drag penalty of ship-fouling biofilms

Lead Research Organisation: University of Southampton
Department Name: Faculty of Engineering & the Environment

Abstract

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Technical Summary

Biofilm fouling on ships leads to costly drag penalties, and the marine coatings industry seeks to develop technologies that will eliminate or reduce "slime". This project explores the feasibility of using marine fouling biofilm mechanical and physical properties as predictors of associated drag, and thus more sophisticated metrics of coating performance than the current standard of percent coverage. Biofouling and coatings experts at International Paint, Ltd and biofilm mechanics experts at University of Southampton will partner to develop and validate two innovate methods and apparatuses for measurement of biofilm drag and mechanical/physical properties on intact, immersed biofilms on marine coatings. With these methods, the teams will compile the first dataset of biofilm drag penalties with respect to the mechanical/physical properties of these compliant materials. The test methods and broader knowledge of biofilm properties and drag will directly benefit coatings research and development, product performance modelling, and fundamental materials science.

Planned Impact

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Description Biofilm thickness measurements derived using software developed in the project were presented by International Paint, AkzoNobel researchers at the International Congress on Marine Corrosion and Fouling, July 2016, Toulons, France, to a multidisciplinary audience, broadcasting the potential of OCT as analytical tool to measure biofilm thickness as an alternative to laser scanning profilometry, microscopy, physical disruption to measure thickness.

Development of a method to accelerate screen marine coatings using spinning disk rheometry will significantly reduce the bottleneck between the design and fabrication of novel anti-biofouling coatings at the bench and in field testing.

We have designed, fabricated and tested a marine biofilm flow cell for in situ determination of drag, structure and viscoelastic properties. The flow cell has been designed for field operation at harbor or onboard a vessel. (870 mm length (L), 10 mm height (H) and 50 mm width (W)) which was constructed by sandwiching together four panels. The bottom and the top panels, made of Perspex, and can be sprayed with corrosion resistant or antifouling marine coatings. Alternatively panmels can be exposed to sea water on hang boards or by mounting to ship hulls then assembled into the flow cell. The bottom panel had machined recesses to insert six Perspex discs (D=40 mm) for rheometer analysis. The side panels are made of clear acrylic to allow natural light to enter from either side. A digital flowmeter (PRS Corrente, AQUAfair) monitored flow rate and the water temperature. The pressure drop (?P) is measured using a differential pressure sensor (PL-692, Omni Instruments). A submersible pump (Aqua Medic DC Runner 9.1) is used to continuously pump fresh sea water through the flow cell. The loss coefficient (k) where was found by measuring the ?P at various flow velocities (u) over the entire pump range (currently 0-4 knots but we plan to extend this range with a m ore powerful pump. The flow cell has been operated continuously at 25 L/min (1.6 knots) for 48 days at the National Oceanography Centre Southampton (NOCS) and monitored during biofilm growth. We have calibrated the system with sandpaper to provide defined roughness and the system behaves as predicted. We have also found that fouling considerably and significantly increases drag. The system is designed so that a window can be installed to non-destructively image changes to the structure and detachment of marine fouling as the speed increases. These experiments will be performed at the end of March.

The system can control and measure flow velocity of sea water and simultaneously record temperture and pressure drop from which we can calculate marine drag. The flow cell can be fitted with coupons coated with

Knowledge transfer within industry partner - engagement activities and review activities have highlighted potential use of OCT to measure other mesoscale features as required by coating scientists, and at least 3 investigative projects within the company have followed our internal presentations.

Anticipated impact: AMT2017 conference presentations, wider knowledge of methods. UPDATE Feb 26 2018: We did present two talks and published abstracts at AMT17: Fabbri, S., Dennington, S., Stoodley, P., Longyear, J. A marine biofilm flow cell for in situ determination of drag, structure and viscoelastic properties. Proceeding from The 5th International Conference on Advanced Model Measurement Technology for the Maritime Industry (AMT'17). 11th - 13th October 2017, Glasgow, UK. pp. 251 - 261. Fabbri, S., Dennington, S., Stoodley, P., Longyear, J. A marine biofilm flow-cell for screening antifouling marine coatings using optical coherence tomography. Proceeding from The 5th International Conference on Advanced Model Measurement Technology for the Maritime Industry (AMT'17). 11th - 13th October 2017, Glasgow, UK. pp. 250. These papers are being submitted to the journal Ocean Engineering
Exploitation Route Our methodology has been published in two peer reviewed articles: Fabbri, S., Dennington, S., Price, C., Stoodley, P., Longyear, J.A. Stoodley, P. 2018. Marine biofilm flow cell for in situ determination of drag and biofilm structure". Ocean Engineering. Accepted 2/24/19 and Fabbri, S., Dennington, S., Stoodley, P., Longyear, J. 2018. A marine biofilm flow cell for in situ screening marine fouling control coatings using optical coherence tomography. Ocean Engineering. 170, 321-328. In addition we are preparing a further methods paper "Measuring the hydrodynamic drag due to biofilms formed on marine coatings using a benchtop rheometer method. Simon P J Dennington, Jennifer Longyear, Clayton Price, Yigit Demirel, Paul Stoodley" which we are planning on submitting to the journal Environmental Science and Technology.
Sectors Aerospace, Defence and Marine,Energy,Environment,Manufacturing, including Industrial Biotechology
URL https://www.dropbox.com/s/w2xqqhnsma289d0/AMT17%20Proceedings.pdf?dl=0
 
Description Knowledge transfer within industrial partner. Biofilm imaging methods developed in the project are being applied to measurement of biofilm physical properties on different coating substrates to investigate interplay between coating properties and biofilm structure. In this capacity, the project output benefits coatings development research streams. The methods are also frequently demonstrated to customers visiting Felling site to demonstrate technical competency, and so contribute positively to the reputation of the company as technology leaders. 2018/2019 is the second year in which an industrial placement student has been employed by International Paint to test coating performance using the matrix flow cell. The scope of work has been expanded to incorporate materials properties, and funding for a related 6-month proof of concept study "Development of synthetic biofilm for calibrating the effect of coatings on reducing marine viscoelastic drag" has been awarded to Southampton and International Paint through BBSRC/NBIC (£ 59,000).
First Year Of Impact 2017
Sector Aerospace, Defence and Marine
 
Description Development of synthetic biofilm for calibrating the effect of coatings on reducing marine viscoelastic drag.
Amount £87,500 (GBP)
Funding ID EP/R513325/1 
Organisation Envision doctoral training partnership 
Sector Academic/University
Country United Kingdom
Start 09/2019 
End 08/2022
 
Description National Biofilm Innovation Centre (NBIC) Proof of Concept (POC)
Amount £59,000 (GBP)
Organisation Biotechnology and Biological Sciences Research Council (BBSRC) 
Sector Public
Country United Kingdom
Start 03/2019 
End 08/2019
 
Description The influence of solutions of an active agent on pregrown biofilms grown from human saliva / plaque using indentation rheometery and confocal microscopy
Amount $568,184 (USD)
Organisation Colgate-Palmolive Company 
Sector Private
Country United States
Start 07/2016 
End 10/2021
 
Description Viscoelasticity and Associated-drag of Artificial and Natural Marine Fouling Biofilms
Amount £29,687 (GBP)
Funding ID 2282598 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Public
Country United Kingdom
Start 09/2019 
End 09/2022
 
Title Design and fabrication of a flow system for studying marine drag and evaluating efficacy of novel antifouling and drag reducing coatings. 
Description The marine biofilm flow cell consists of a rectangular channel (870 mm length (L), 10 mm height (H) and 50 mm width (W)) which was constructed by sandwiching together four panels. The bottom and the top panels, made of Perspex, which can be sprayed with inert corrosion resistant marine coatings or anti-fouling coatings. The system is designed to be operated in the field and an ongoing field trial the system has been operated continuously at 25 L/min (1.6 knots) for over 60 days at the National Oceanography Centre Southampton (NOCS) and monitored during biofilm growth. The system has been designed to continuously monitor pressure drop and temperature, which can be used to calculate drag. The systems has been designed to incorporate panels which have been immersed in seawater on ship hulls or immersion boards from pontoons. The system incorporates rheometer disks so we can relate data generated from the flow cell with our novel rapid screening rheometer system (described in a separate research tool entry). The side panels were made of clear acrylic to allow natural light to enter from either side. The system can be fitted with a clear window to observe how the viscoealstic biofouling responds to changes in flow velocity and the effect on drag as well as monitor for detachment ans shedding of biofouling. Currently the system can operate up to approximately 4 knots but this is planned to increase with the addition of a more powerful pump. 
Type Of Material Technology assay or reagent 
Provided To Others? No  
Impact This system will be used by the partner company in their R&D programme to develop more efficient anti-drag and anti-fouling technologies for use in the marine industry. Elucidating how marine fouling interacts with complex fluid flow at the interface will be used to better understand how antifouling coatings work. The designs and operations will be made available to other companies through planned upcoming presentations and a publication in peer reviewed journals. 
 
Title Development of a rheometer method for rapid screening of marine coatings and influence of bofouling on ship hull drag 
Description Duplicate rheometer torque measurements on discs spin-coated with the same coating (Intershield Bronze 300 primer) and having similar surface roughness were highly reproducible. Temperature control was identified as a parameter requiring closer control in future during measurements. Discs were fouled by immersion in the sea at Southampton docks for 2, 4, 6 and 8 weeks before drag measurements were made. After the first 2 week exposure period steps were taken to prevent grazing of the disc surfaces by fish. The amount of slime fouling on individual discs varied, and the drag measurements reflected this. Nevertheless statistically significant differences in drag were observed between the different exposure durations. Calibration was carried out using varying grades of sandpaper roughness applied to test discs. A linear relationship between measured surface roughness and the disc coefficient of momentum (torque coefficient) was observed. The method is considered to be reliable and reproducible enough to use in routine testing of marine coatings. 
Type Of Material Technology assay or reagent 
Year Produced 2019 
Provided To Others? No  
Impact The work has been submitted to the peer reviewed journal "Biofouling". We are in process of submitting a revision. 
 
Description Hydrodynamic considerations of marine fouling 
Organisation Newcastle University
Country United Kingdom 
Sector Academic/University 
PI Contribution I have collaborated on Dr. Jinju (Vicky) Chen, senior Lecturer in Biointerface Engineering on her NBIC POC funded project titled "Develop a computational tool for marine biofilm management".
Collaborator Contribution To investigate the interplay of flow, biofilm mechanics, erosion and drag, Dr. Chen's team measured various properties of biofilms in-situ with a previously unachievable measurement depth. Biofilm culturing and drag measurements were carried out using a flow cell developed by the Innovate UK - UoS and AkzoNobel partnership specifically for biofilm OCT imaging. By combining the flow cell with NCL's existing fully automated OCT micro-positioning system and prototype co-registerd air-jet indenter, unique measurement capabilities, was used to capture repeated biofilm biomechanical measures during erosion across the full extents of the metre-long test pieces. Replication will address biofilm spatial heterogeneity and bridge the three orders of magnitude scale difference between imaging and drag measurements.
Impact As an outcome of this work I am supporting furthering the collaboration in an NBIC POC proposal "Develop novel biomimetic surfaces to prevent biofilm formation on catheters".
Start Year 2020
 
Description BBSRC Innovate UK Biofilm research informs marine coatings design 
Form Of Engagement Activity A magazine, newsletter or online publication
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact BBSRC Innovate UK online news brief on the project
Year(s) Of Engagement Activity 2019
URL https://bbsrc.ukri.org/documents/biofilm-research-informs-marine-coatings-design/
 
Description Frontiers in Engineering Biology research group science meeting 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact J Longyear. Research questions in aquatic biofilm fouling on ship coatings. Invited lecture. Newcastle University, 8 December 2016. (Frontiers in Engineering Biology research group science meeting.)
Year(s) Of Engagement Activity 2016
 
Description Industrial presentation: Bacterial Biofilms are a Drag from Dental Plaque to Marine Biofouling. International Paint, Newcastle UK. 9/25/17. 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Industry/Business
Results and Impact Industrial presentation: Bacterial Biofilms are a Drag from Dental Plaque to Marine Biofouling. International Paint, Newcastle UK. 9/25/17.
Year(s) Of Engagement Activity 2017
 
Description Poster Presentation 18th International Congress on Marine Corrosion and Fouling. Toulon. 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Other audiences
Results and Impact A portion of the data arising from the project was presented in the form of a poster: PT S9-8 Characterisation of marine biofilms grown under different hydrodynamic regimes and their impact in ship operational efficiency. Jack HAYDEN, International Paint Ltd, UK.
Year(s) Of Engagement Activity 2016
URL http://icmcf2016.univ-tln.fr/
 
Description Project Overview. InnovateUK/BBSRC Biofilms Cohort-Building Event. 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Other audiences
Results and Impact S Fabbri and J Longyear. Project Overview. InnovateUK/BBSRC Biofilms Cohort-Building Event. Manchester, 12th July 2016. (One day conference including presentations by most of the feasibility study projects funded by Phase 1 Biofilms Programme call, networking, and workshop to contribute to shaping UK Biofilms Programme)
Year(s) Of Engagement Activity 2016
 
Description Project report Big Biology Day. AkzoNobel 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Industry/Business
Results and Impact S Fabbri. Biofilm viscoelasticity. Optical coherence tomography and biofilm imaging. (Posters and demonstrations.) Big Biology Day. AkzoNobel, Gateshead, 4 November 2016. (Internal company science festival to promote understanding of biofouling research projects by interactive displays, posters, videos, etc.).
Year(s) Of Engagement Activity 2016