No longer is it necessary to just specify simple ball bearings or use ball bearings packed in grease and hope corrosion doesn't lock up the bearings at a critical time when used in seawater spray or immersions environments. New technologies have brought more choices and options to designers and users of bearings in marine environments. New materials for plain bearings and bushings, plastic ball bearings that can operate entirely without lubrication, and type 316 stainless steel ball bearings bring new utility and performance to marine equipment.
For slow speeds and moderate loads marine equipment designers were restricted to such single polymer plain bearings as the type bushings, or Delrin type bushings. While these work fine within their limited parameters, when speeds or loads increase, or bearing wear is of concern, the limitations of these bearings becomes apparent very quickly. Nylon bushings absorb water and their running torque increases greatly when swollen reducing the internal clearance necessary for a free turning joint. Nylon and Delrin also wear out quickly whenever dust, dirt or gritty particles, common in seawater are present.
