This Technical Report describes a velocity-area method which can be carried out using three verti-cals only, without significant loss of accuracy, and gives advice on when such a "short-cut" method should be used.
The method specified in this Technical Report is not an alternative to the velocity-area method specified in ISO 748, which gives accurate results and should be used under normal conditions. This short-cut method has a limited field of application and is in-tended for use only in special circumstances, ex-amples of which are given in clause 7.