Heavy Duty (H)
Operation hours are unlimited per year, at average load is up to 90%, at full load is up to 80%.
Typical gearbox ratio: 2.5 ~ 6
(Fishing trawler, Tug boat, Pushing vessel, Cargo boat, Freighter, Ferry).

Medium Duty (M)
Operation hours are up to 3000 per year, at average load is up to 70%, at full load is (up to 30% / 4hrs per 12 hour operation period).
Typical gearbox ratio: 2 ~ 3.5
(Fishing trawler, Pilot boat, Escort boat, Passenger boat, Freighter, Ferry, Cruising vessel).

Light Duty (L)
operation hours are up to 1000 per year, at average load is up to 50%, at full load (up to 20% / 2hrs per 12 hour operation period).
Typical gearbox ratio: 1 ~ 2.5
(Light weight fishing boat, Yacht, Cruising vessel, Fast boat, Fire pump).