Chryssostomtdtis 
and ¢ is the broadness factor assumed to equal 
0.60 for the present study. 
In order to satisfy the requirement that the 1/10 highest values 
of vertical acceleration does not exceed one g anywhere along the ship's 
length the inequality Vmo < 0.217 must be satisfied. 
(ii) the probability ate that the amplitude of relative motion at 
station 1 will exceed the freeboard at station 1 (f,,) be 
less than 0.01. 
From Reference 12 
Z yn 
= -f 
“i Pei w = See 
2 
where A = “2(l=e  /Z\m 
rm O 
c) For the safety of the ship the probability, P 
station 2 should not exceed 0.01. 
sg of slamming at 
202 2 22 
= -(f /A iV A 
a Te | ( af rm er / a 
where f, is the draft at station 2 
Ms is the threshold critical velocity assum- 
ed to equal 12 ft/ sec fora 500 ft. 
ship and scaled according to Froude for 
other ship lengths 
2 
and Ay =1 Z(1=% /2)mo, 
Once the motion indices are calculated the speed determined 
from resistance considerations is reduced (if necessary) until the 
motion criteria are satisfied. If the speed is reduced to 3.5 knots 
(speed assumed to be necessary for the maintainance of a prespecifi- 
ed course) and the motion criteria are not satisfied, no further speed 
1600 
