The aim of this study is to investigate experimentally the fracture toughness of sandwich systems with the PVC foam core in marine environment with a Mode-I Cracked Sandwich Beam (CSB) test arrangement. Five CSB specimens at each condition were tested. To get the values under marine environment, one set of specimen was conditioned in a 5% solution of NaCl for a 120 h period at a constant temperature of 50 o C. It has been found that the fracture toughness of the PVC foam core material slightly increases under marine environmental conditions. It can be concluded that under the conditions in this study the system with the PVC core was largely unaffected by the immersion process.

In this study, the recruitment and succession of biofilms were examined on static panels representing a boat hull exposed to seawater. Panels were coated with five types of gelcoats to compare the effect of antifouling agents on the forming of biofilms. Pesticide and elemental silver-based additives in two weight ratios (0.003 and 0.006) were used as the antifouling agents for the gelcoat. The temporal variation in recruitment of biofilms was examined by isolation of attached bacteria during a boat storing period in a marina located along the Izmir Bay (Turkey). It was found that the gelcoat with silver ion had slight superiority over the counterparts in this study. The first 15 days of bacteria formation was the significant period for examining the antifouling performance of a coating material.