GP Catamaran Ceramic Mainsheet System - 2800Harken's Grand Prix mainsheet systems are critically important options for high performance beachcats like the Nacra 17 or F18s. The high efficiency blocks making up these systems feature insert molded ceramic bearings that almost eliminate rolling resistance, greatly improving power transfer to the crew for easy, precise trimming. These compact blocks feature hardcoat anodized sideplates that envelop composite sheaves for easy disassembly reassembly.