抄録
The estimation of collision number for a ship passing through a certain water is often requested. The first approximation of this collision number can be easily obtained as the product of (L/L_0) and the coefficient, F, mentionned in the title, where L is the length of the ship between perpenPiculars and L_0 is equal to 32m. The coefficient is defined as the number of collided ahips in the water range in unit time divided by the traffic volume summed up using (L/L_0) as the weighting faotor. The coefficients for important harbours as well as several congested straits are given and compared in a figure. An interpretation of the coefficient is tried placing Fujii's equation at starting line. Result of analysis gives the method of adjustment for minor change in the traffic volume in the water range being considered.
