HC600A HCD600A HCT600A HCT600A/1 HC600 series marine gearbox HCD600A MARINE GEARBOX MAX.1365HP ... "Rate"will rise 8% if high-flexible coupling is used. HCT600A/1 MARINE GEARBOX MAX.1260HP at 2100RPMEngine Speed:1000~2100RPMRatio8 ... "Rate"will rise 8% if high-flexible coupling is used. HCT600A MARINE GEARBOX MAX.1260HP at 2100RPMEngine Speed:1000~2100RPMRatio6.066 ...