Information from SSRC - Universities of Glasgow and Strathclyde, regarding the passenger ship heeling moment formulas in draft regulation II-1/7-2 Survival Against Heeling Moment (in draft Harmonised Regulations) Heeling Moments Applicable ( the values are calculated for a sample ship) Heeling Moment Applied 1945 ton-m 3179 ton-m M heel = max (M passengers, M wind, M survival craft) … ! Heeling Moment Due to Side Wind Maximum wind speeds (gusts) are determined during each individual averaging period. Gust information is important for risk assessment studies of damage to constructions and buildings, and in our case creating a substantial heeling moment on a vessel with relatively large superstructure. The duration of the gust is an important consideration and is often related to the intended application. Some applications require information about extreme values of the shortest gusts (~1 second duration), while in other cases, the damaging gusts are those that blows the entire structure (5-10 seconds duration). Heeling Moment Due to Side Wind Heeling Moment Due to Side Wind Heeling Moment Due to Side Wind Wind Speed, Wind Gust V(t) Mean Speed, Vmean Wind Speed, Time, t Wind Speed V(t) Spectrum, Max. speed Swind (ω ) Mean Speed, Vmean PDF Min. speed frequency, ω for a conservative consideration Maximum Heeling Moment Wind gusts blow in a direction that follows the wave progression; therefore this should be applied consistently to the most conservative damage scenario without overlooking the physical reality. Since the most critical damage flooding scenario occurs when the damage opening faces to incoming waves at 90 Degrees, therefore the wind can be taken as a corrective factor for the heeling that might be present due to damage in the first place. The survival factor-s with all its components ought to consider survival in waves. The existing proposal: ignores this fact and penalises the vessels with a large lateral profile. M heel = Max [ M passengers , M wind , M survival craft ] Maximum Heeling Moment It is therefore suggested that a suitable wind speed value must be calculated considering maximum and minimum wind speed variations, perhaps mean wind speed can be used, then this would result in the net heeling moment applicable being obtained through passenger heeling moment being reduced by about 1/3 for a typical passenger vessel. The foregoing argument then replaces the maximum moment consideration as follows: M heel = Max [ (M passengers - M wind) , M survival craft ] Ignoring wind altogether can be considered if a conservative approach were to be followed but at least it will not be as unrealistic as the currently adopted approach.