Silyl acrylate copolymers are promising materials for marine antibiofouling. However, their structures need optimizing to improve their erosion and mechanical properties. We have prepared copolymer of 2-methylene-1,3-dioxepane (MDO), tributylsilyl methacrylate (TBSM) and methyl methacrylate (MMA) via radical ring-opening copolymerization. Such polymer has a degradable backbone and hydrolyzable side groups. Our study demonstrates that as the ester units in the backbone increase, the degradation rate increases but the swelling decreases in seawater. The degradation is controlled by the polymer composition or the molar ratio of the ester units in the backbone to the silyl ester side groups. Moreover, such polymer can serve as a carrier and controlled release system for organic antifoulants. Marine field tests show that the system consisting of the copolymer and organic antifoulant has good antifouling performance depending on the polymer composition. It can effectively inhibit the colonization and growth of marine organisms when MDO content is above 20 wt %.