Dual Class:- A dual class vessel is one which is classed by two Societies between which there is a written agreement regarding sharing of work, reciprocal recognition of surveys carried out by each of the Societies on behalf of the other Society and full exchange of information on the class status and survey reports.
Double Class:- A double classed vessel is one which is classed by two Societies and where each Society works as if it is the only Society classing the ship, and does all surveys in accordance with its own requirements and schedule.
