ABSTRACT
In design of ice going vessels, the ice load has been traditionally idealized as a horizontal rectangular pressure patch. When the pressure patch is applied on transversally framed side structure, the load is shared by several frames, whereas on longitudinally framed structure, the load is carried by one or two frames. Therefore, the traditional method has been to use one design formula for transverse framing and another one for longitudinal framing. These formulas work very well for parallel midbody region, but for the shape regions in bow and stern, the actual case is neither purely longitudinal nor transverse. Moreover, in some designs, frames are canted instead of transverse or longitudinal. In development of the IACS PC rules, these needs have been taken into account by introducing angle omega, which considers the relative geometry between load patch and framing more accurately than previously used division into transverse and longitudinal framing. However, no way for calculating this angle has been provided in the rules and while approximate angle can be estimated visually or graphically, formulas for calculating the angle would be useful. In this paper, formulas for calculating the omega angle for all typical framing solutions and general hull geometry are presented.
