| No longer is it necessary to just specify simple | | | | Where low torque anti-friction type bearings are |
| Nyliner bearings or use ball bearings packed in | | | | needed, plastic ball bearings assemblies are now |
| grease and hope corrosion doesn't lock up the | | | | available. These are generally constructed of |
| bearings at a critical time when used in seawater | | | | Acetel polymer rings and cages and use stainless |
| spray or immersions environments. New | | | | steel balls. Originally developed for swimming pool |
| technologies have brought more choices and | | | | cleaners and immersion in photo developing |
| options to designers and users of bearings in | | | | solutions, these bearings are finding favor in a |
| marine environments. New materials for plain | | | | wide range of marine, saltwater applications. |
| bearings and bushings, plastic ball bearings that can | | | | Self-steering gear for sailboats, for instance, relies |
| operate entirely without lubrication, and type 316 | | | | on low torque rotation of shafts sensitive to |
| stainless steel ball bearings bring new utility and | | | | minor variations in wind direction. A plastic raced |
| performance to marine equipment. | | | | ball bearing fits the bill perfectly, can operate |
| For slow speeds and moderate loads marine | | | | entirely without lubricants, and may be employed |
| equipment designers were restricted to such | | | | in the salt spray zone or completely immersed in |
| single polymer plain bearings as the Nylon "Nyliner" | | | | seawater4 without ill effect. Other application |
| type bushings, or Acetel (Delrin) type bushings. | | | | includes wind directional sensing gear, rotating |
| While these work fine within their limited | | | | antennas (satellite, radar, etc.) and other places |
| parameters, when speeds or loads increase, or | | | | where a zero maintenance lightly loaded ball |
| bearing wear is of concern, the limitations of | | | | bearing is needed. |
| these bearings becomes apparent very quickly. | | | | Where there are heavier loads and a need to |
| Nylon bushings absorb water and their running | | | | operate without lubrication, type 316 ball bearings |
| torque increases greatly when swollen reducing | | | | are now available on the market. These utilize |
| the internal clearance necessary for a free turning | | | | stainless steel rings, stainless steel balls, and |
| joint. Nylon and Delrin also wear out quickly | | | | generally plastic cages. These ball bearings can also |
| whenever dust, dirt or gritty particles, common in | | | | operate above or below the waterline, are able to |
| seawater are present. | | | | withstand substantial loads without lubrication, and |
| The new polymeric alloys, combining the features | | | | have been proven to be corrosion free for years. |
| of many polymers are proving themselves a boon | | | | Some marine applications type 316 bearings have |
| for bushings for seawater use. Materials such as | | | | found favor in, include watertight ship doors, |
| Polyphenylene Sulfide (PPS or Ryton) PTFE | | | | fairlead pulleys, bow rollers, stabilizers, and a host |
| (Teflon) and Molybdenum Disulfide composites are | | | | of other high load, slow to moderate speed |
| offering greatly increased load carrying capabilities | | | | saltwater applications. |
| with substantially longer lives. Such bearings can | | | | No longer does the marine designer or shipboard |
| be not only be used in bushings in the on-deck, | | | | equipment engineer have to rely on constant |
| salt spray environments, but also fully submerged | | | | maintenance, frequently packing all bearings with |
| in environments where traditional cutlass type | | | | grease to keep everything rolling smoothly on |
| bearings are used. Many other modern polymeric | | | | ships and boats exposed to salt spray, saltwater |
| alloys are now available to accommodate a wide | | | | immersion or other marine environments. |
| variety of application parameters. | | | | |