Simplified Propulsion Ability Assessment Sample Clauses

Simplified Propulsion Ability Assessment. The starting point is the system of equations (16)-(18), which has to be solved for all possible seaway directions to demonstrate that the ship is able to keep forward speed of at least 6.0 knots in seaway from any direction. Noting that bow seaways are most critical for required power at a given speed (Figure 54, middle plot), it is enough to consider only seaways from 0 to about 60 off-bow in the assessment. Further, neglecting the influence of drift on the required thrust and required power allows omitting equations (17) and (18). Thus only eq. (16) needs to be considered, and only in head waves: Xs  Xw  Xd  XR  T (1 tH )  0 However, it is important to keep in mind that the time-average longitudinal force due to waves be taken as the maximum force in mean wave directions between 0 and 60 off-bow. X d should The contributions X s , X w , X d and X R can be found using any method from the Comprehensive Assessment (empirical, numerical or experimental). However, it seems logical to allow using also simpler approximations for these terms in the Simplified Assessment.