Schaefer blocks rely on a variety of sheave designs, materials and scorings. We do not recommend the replacement of Schaefer sheaves in the field. We suggest the return of Schaefer Blocks to our factory for inspection and/or replacement of worn or UV affected sheaves. Schaefer sheaves are designed to be compatible with Schaefer products, and are not intended for use in other manufacturers’ blocks. There is a risk of incompatibility or failure when using Schaefer sheaves in blocks manufactured by anyone other than Schaefer Marine.
Delrin Ball Bearing: Delrin™ sheaves with Delrin™ Ball Bearings are used in line application to reduce friction. To provide the maximum load bearing capability, we designed our Delrin™ ball bearing sheaves and inner races with curved surfaces to match the ball races. The resulting sheave has a much higher safe working load than other manufacturers’.
Aluminum Universal Circuit Sheaves (UC): These extremely low friction ball bearing sheaves accommodate both line and wire. High strength self-contained Delrin™ bearing package and Nomex™/Teflon™ self-lubricating bushing is used in all “UC” sheaves. The combined benefits of the design mean easier turning under the heaviest of loads.
Aluminum: This configuration accommodates both line and wire, providing a chafe-free surface for line while giving full support to wire to prevent flattening. Hardcoat Anodized 6061-T6 Aluminum offers superior strength and corrosion resistance.