Abstract
In LNG carriers, a part of the cargo is converted to boil-off gas due to heat from the open air and ship motions. Steam turbines have been predominantly used for current propulsion systems of LNG carriers, because this boil-off gas can be used as fuel for boilers. However, in recent years the number of electric propulsion systems using dual-fuel diesel generator engines has increased as an alternative to steam turbine systems. Last November, NIPPON KAIJI KYOKAI (ClassNK) issued the "Guidelines for Dual-Fuel Diesel Engines". These guidelines describe the construction and applicable rules for dual-fuel diesel engines. The IGC Code and Chapter 16, Part N of the Society's Rules prescribe the requirements that apply to dual-fuel diesel engines on the "Use of cargo as fuel". Furthermore, "Annex 3" and "Annex 4", Part N of the Guidance to the Society's Rules describe the requirements in detail for dual-fuel diesel engines. This paper gives an overview of the Guidelines mentioned above.
