Construction, Delivery, and Testing of a Flow-Cell to Measure Adhesion Strengths of Hard-Fouling Organisms on Foul-Release Coatings in Hawaii

摘要

A precision flow cell for measuring shear stresses exerted on hard fouling organisms attached to experimental coatings was constructed at Harbor Branch Oceanographic Institution, delivered to the Kewalo Marine Laboratory (KML) of the University of Hawaii, assembled, and calibrated. The flow cell was equipped at the KML with a binocular microscope to which a video camera is attached, allowing simultaneous viewing and videotaping of attached hard-fouling organisms (principally the polychaete tube worm Hydroides elegans and the barnacle Balanus amphitrite) as they are subjected to increasing flow velocities, and thus shear stresses, in natural seawater. Tests of glass surfaces demonstrated that the hard foulers could not be removed by shear forces comparable to those on the hull of a large naval ship under near maximal speed. Small hard-fouling invertebrates were similarly not removed from a series of silicone-based experimental coatings provided by General Electric's paints dept. We await delivery of other coatings by ONR, DARPA or private developers to further exploit this excellent, precision instrument. Because of the lack of materials for testing, no presentations (other than to ONR) or publications have resulted from this instrument yet.