Influence of Coating Hardness on Plowing of Barnacles Crust on Tar Epoxy Paint Coating

Abstract

To investigate the plowing phenomenon of barnacles crust on the paint coating, steel test plates were separately coated with each of 4 types of paint varying in tar epoxy resin contents and were suspended in the sea. During 30 months of suspension, change in Vicker's hardness of coating was measured and attachment of barnacles and the plowing on coatings were observed. No plowing of barnacle was observed on the coating containing more than 40% v/v resin. The hardness of such coating was 1.6MHV, before suspension, but increased to 2.0MHV after 30 months. However, a high degree and frequency of plowings was observed on coating having 25% v/v resin with an initial and final hardness of 0.8 and 0.9MHV, respectively. Balanus trigonus and Megabalanus rose were observed as dominant glowers on the coatings. Especially, the latter is a more dangerous species with regard to plowing. Serious plowing was observed mostly on individuals larger than 20mm in crust diameter.