Frictional resistance comprises more than 60% of the total resistance for most merchant ships. Active and passive devices have been used to reduce frictional resistance. but the most effective and practical device is an air lubrication system. Such systems have been applied in several ships. https://www.spidertattooz.com/Kaiser-Copy-Stand-RS-1-with-RA-1-Arm-40-Counterbalanced-Column-and-18-x-20-Baseboard/