Abstract: An incinerator 20 for disposing of boil-off gas on an LNG carrier comprises a combustion chamber 42 wherein the boil-off gas admitted at 40 is burned in the presence of combustion air admitted at 44, producing a flame 46 and combustion products C. Dilution air A is delivered into the combustion chamber 42 and mixed with the combustion products C to produce a diluted mixture M. The combustion chamber 42 has an inner wall 48 and an outer wall 50 together defining a first passage 52 through which the dilution air A is passed before being mixed with the combustion products C, whereby the dilution air A cools the incinerator 20. The dilution air A in the first passage 52 also provides a thermally insulting layer limiting radial heat transmission from the combustion chamber 42. A flue 58 is configured and arranged so that the flame 46 is enclosed.