Prediction of Ship Slamming at Sea 



Fig. 1 - Pressure on the keel 

 plate as a function of impact 

 velocity (MARINER, Station 2, 

 light draft, ship speed 10 knots, 

 moderate Sea State 7) 



20 30 40 



Relative Velocity in Ft./Sec 



Thrtihokl VModty 

 12 Ft/S»e. 



^VV /BOW EMERGENCE, b-w > H 



WAVE MOTION 



BOW (FOREFOOT) MOTION 



Fig. 2 - Explanatory sketch of bow emergence 



taken as positive. The distance between these two zero- lines is equal to the 

 ship draft, H, at a specific location, x (in this example, Station 2), for which 

 the probability of slamming is evaluated. Note that this draft is not necessarily 

 the design draft. Next, let r = b- w; then the relative motion, r, must always 

 be positive and greater than H when bow emergence occurs. 



549 



