Drag resistance of ship hulls: effects of surface roughness of newly applied fouling control coatings, coating water absorption, and welding seams

The turning of caprolon with the use of cutting fluid is investigated. It is established that when turning with a simultaneous supply of a water emulsion of a water repellent to the cutting zone, the water absorption of caprolon decreases and the quality of the machined surface increases. Keywords: caprolon, turning, water absorption, water repellent emulsion, surface roughness, chip formation. [email protected]

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A High Speed Boat for the Hydrodynamic Testing of Fouling Control Coatings

10.5957/attc-2017-0009 ◽

2017 ◽

Author(s):

J. Travis Hunsucker ◽

Harrison Gardner ◽

Geoffrey Swain

Keyword(s):

High Speed ◽

Video Camera ◽

Load Cell ◽

Structure Characterization ◽

Hydrodynamic Drag ◽

Experimental Uncertainty ◽

High Definition ◽

Fouling Control ◽

Drag Forces ◽

Fouling Control Coatings

An 8.2 m high speed boat was modified to measure the drag and to provide real time video of ship hull fouling control coatings under boundary layer conditions that developed at speeds up to 15 m/s. It consists of a through hull Hydrodynamic Drag Meter (HDM) placed in a wet-well built into the aft section of the boat. The HDM consists of a load cell attached to a floating element balance and a high definition video camera to observe fouling. Test panels are attached to the load cell such that they remain flush with the hull. Fouled test panels are placed in the facility to observe the velocities required for fouling removal and changes in drag forces associated with different fouling community structure. Characterization studies of the HDM were undertaken to understand the overall accuracy of the novel testing system. These experiments included 1) Smooth acrylic drag measurement with the HDM and a Preston tube and 2) Drag measurements with the HDM on panels with 60- grit and 220-grit sandpaper. Smooth panel wall shear stress values obtained using the HDM were within experimental uncertainties of results from Preston tube. Roughness function values for 60-grit and 220-grit sandpaper agree within the experimental uncertainty of the Nikuradse-type roughness function for uniform roughness. Skin friction coefficients of a smooth panel determined on the HDM had an experimental uncertainty of around 5% for Froude numbers greater than 1. Roughness function values for a 220-grit and 60-grit sandpaper surface had maximum uncertainties of 11% and 13% respectively.

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Effects of Alkaline Treatments on the Tensile Strength of Napier Grass Fibres

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.695.340 ◽

2014 ◽

Vol 695 ◽

pp. 340-343 ◽

Cited By ~ 6

Author(s):

J.A. M. Haameem ◽

M.S. Abdul Majid ◽

M. Haslan ◽

Mohd Afendi ◽

E.A. Helmi ◽

...

Keyword(s):

Surface Roughness ◽

Tensile Strength ◽

Tensile Test ◽

Water Absorption ◽

Chemical Treatment ◽

Moisture Absorption ◽

Single Fibre ◽

Napier Grass ◽

High Moisture ◽

The Poor

This paper presents the experiment test of the Napier grass fibres to determine the tensile strength of the Napier grass fibre. . Napier grass fibre is a natural source of fibre which is extracted from the internodes of Napier grass stems. Napier grass fibres were extracted trough conventional water retting process. However, the main disadvantages of natural fibres in composites are the poor compatibility between fibre and matrix and the relative high moisture absorption. These Napier grass fibre then undergoes alkaline chemical treatment using sodium hydroxide (NaOH) to improve the surface roughness and to minimize the water absorption into the cellulose. The treatment is conducted with different concentration of NaOH at 5%, 10%, 15% and 20% respectively. The single fibre tensile test was conducted using Instron micro tester. Based on the tests conducted, the results show that the fibre treated 10% concentrations yield the strongest tensile test compared to untreated Napier grass fibre.

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Effects of water absorption and surface roughness on the bioreceptivity of ETICS compared to clay bricks

Building and Environment ◽

10.1016/j.buildenv.2014.03.018 ◽

2014 ◽

Vol 77 ◽

pp. 20-28 ◽

Cited By ~ 31

Author(s):

Marco D'Orazio ◽

Gianluca Cursio ◽

Lorenzo Graziani ◽

Lucia Aquilanti ◽

Andrea Osimani ◽

...

Keyword(s):

Surface Roughness ◽

Water Absorption ◽

Clay Bricks

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Fouling control coatings using low surface energy, foul release technology

Advances in Marine Antifouling Coatings and Technologies ◽

10.1533/9781845696313.4.693 ◽

2009 ◽

pp. 693-708 ◽

Cited By ~ 14

Author(s):

R.L. Townsin ◽

C.D. Anderson

Keyword(s):

Surface Energy ◽

Fouling Control ◽

Low Surface Energy ◽

Fouling Control Coatings

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Using Hydrodynamic Testing to Assess the Performance of Five Fouling Control Coatings Immersed at Two Field Sites along the East Coast of Florida

10.5957/attc-2017-0008 ◽

2017 ◽

Author(s):

J. Travis Hunsucker ◽

Harrison Gardner ◽

Geoffrey Swain

Keyword(s):

High Speed ◽

East Coast ◽

Immersion Test ◽

Fouling Control ◽

Drag Forces ◽

Fouling Release ◽

Fouling Control Coatings ◽

Fouling Organisms ◽

Hydrodynamic Testing ◽

Static Immersion

Static immersion studies are commonly used to assess the performance of fouling control coatings. While these tests provide valuable data, it is also of importance to understand the drag forces associated with the accrued fouling communities and the velocities required for fouling removal. Combining the measurements of hydrodynamic testing with those from static immersion testing can help in predicting the performance of coatings prior to their consideration for use on Navy vessels. Replicates of five commercially available coatings (three fouling release coatings and two biocide based coatings) were deployed at two static immersion test sites located along the east coast of Florida (Port Canaveral and Sebastian Inlet). After four months of immersion, the panels were removed, photographed, subjected to known water velocities in a high-speed boat modified for hydrodynamic testing. Each panel was run at 5 m/s for 10 minutes, photographed, and then run at 10 m/s for 10 minutes. The drag forces were measured at speeds of 3, 6, 8.8 and 10 m/s for 1 minute each. Photographs taken before, during, and after hydrodynamic testing were also visually analyzed. After testing adhesion measurements were taken to determine the attachment strength of any hard fouling organisms which remained on the panels. The data collected from this series of tests, enabled the fouling control and fouling release properties of each coating to be characterized.

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