The effects of mast height and centre of gravity on re-righting have been investigated experimentally using free and captive models. Free model motions were measured using six degree of freedom photogrammetry. Captive model forces were measured using a six component force balance. The results have shown that a relatively small increase in mast height has a much greater effect than the increase in limit of positive stability used in the experiments. It would appear from the results that the overriding factors influencing rerighting in these experiments are the mast height and the wave height and steepness.