Big Boat sheaves are available for special applications as well as for replacement sheaves in Big Boat blocks. Made of Hardkote-anodized, Teflon-impregnated 6061-T6 aluminum, sheaves feature Torlon rollers to carry high radial loads and carbon-black Delrin balls to support sideloads and provide UV protection. Select sheaves based on load-carrying capability. Installation requires clamping or securing inner race. Use for: Mainsheets Spinnaker sheets Afterguy/foreguy Footblocks Sheave Dia.: 3" Width: 7/8" Center Hole Dia.: 3/8" Max. Working Load: 4950lb. Breaking Load: 9900lb.