GASKET 3538578 - Caterpillar

The use of the vessel must be known for the rating to match the operating profile.In selecting a rating for a specific application, the most important consideration is the time that is spent at full throttle. These rating definitions identify the percent of time at full throttle. The definitions also identify the corresponding times below rated rpm.A (Unrestricted Continuous) - Vessels operating at rated load and rated speed up to 100% of the time without interruption or load cycling (80% to 100% load factor). Typical operation is 5000 service hours to 8000 service hours per year. Typical applications may include the following vessels: freighters, tugboats and bottom drag trawlers.B (Heavy Duty) - Vessels operating at rated load and speed up to 80% of the time with some load cycling (40% to 80% load factor). Typical operation is from 1000 service hours to 3000 service hours per year. Typical applications may include the following vessels: cold-water trawlers, purse seiners, crew boats, supply boats, ferries and towboats.C (Maximum Continuous) - Vessels operating at rated load and rated speed up to 50% of the time with cyclical load and speed (20% to 80% load factor). Typical operation is from 2000 service hours to 4000 service hours per year. Typical applications may include the following vessels: ferries, harbor tugs, fishing boats, offshore service boats, displacement hull yachts and short trip coastal freighters.D (Intermittent Duty) - Vessels operating at rated load and rated speed up to 16% of the time (up to 50% load factor). Typical operation is from 1000 service hours to 3000 service hours per year. Typical applications may include the following vessels: offshore patrol boats, customs boats, police boats, fishing boats, fire boats and harbor tugs.E (High Performance) - Vessels operating at rated load and speed up to 8% of the time (up to 30% load factor). Typical operation is from 250 service hours to 1000 service hours per year. Typical applications may include the following vessels: pleasure craft, harbor patrol boats, harbor master boats, fishing boats and patrol boats.
Operating engines above the rating definitions can result in shorter service life before overhaul.
For more information about the engine rating, refer to your Application and Installation Guide or contact your Cat dealer.