The hull form may be approached in a number of ways, such as the parent hull method. The parametric analysis can also be used to develop a desired set of length, breadth, draught, and depth as well as coefficients of form from similar ships to provide an adequate start point. For ships with specialized bows and sterns (such as icebreakers), a midship section can be developed to suit the cargo, to which a suitable ends can be worked in. On further spins of the spiral, hullform is refined to minimize wasted volume and ensure adequate displacement. Any deficiencies of stability, resistance, or arrangement will also be corrected.