Sufficient Propulsion and Steering Ability Check. The simplest assessment procedure, Sufficient Propulsion and Steering Ability Check, is based on pure empirical formulae to define the required installed power as a function of main ship parameters. The formulae proposed below are based on the application of the comprehensive propulsion and steering assessment procedures to over 400 bulk carriers, tankers, container ships and general cargo vessels equipped with two-stroke low-speed diesel engines, a fixed-pitch propeller and a conventional rudder. For each ship, the maximum significant wave height was found, at which the required brake power is equal to the available brake power, separately for steering and propulsion criteria. Based on these results, MCR was approximated as empirical formulae of hs, for each combination of main ship parameters, and then, the required installed power was found that satisfies the standard significant wave heights for propulsion and steering proposed in section 2.6.3. The resulting empirical formulae are, for propulsion ability requirement B pp MCR 0.21 C0.5 L2 , where MCR, kW, is the required installed power in terms of the maximum continuous rating of the engine, and for the steering ability requirement L MCR 0.15 c R pp , R pp m R where c L T 50 A* , and A* min2A / 3, Ap . R R R Figure 55 compares these empirical formulae with the results of the comprehensive assessment; ideally, the Sufficient Propulsion and Steering Ability Check should provide the same or slightly more conservative results than the Comprehensive Assessment. Testing of the proposed formulae by all interested stakeholders and its validation are required to approve / improve them; it should be noted that these formulae are suitable only for vessels equipped with two-stroke low-speed diesel engines, a fixed-pitch propeller and a conventional rudder; for other types of engine, propulsion and steering the simplified or comprehensive assessment should be used.
