Approximation of the added resistance of ships with small draft or in ballast condition by empirical formula

Abstract

An attempt was made to extend and further tune the existing formula for approximating the added resistance in head seas to cover a wider range of speed and to account the impact of loading conditions; a new parameter based on B/T was introduced after conducting extensive parametric study to capture the influence of draft on the added resistance; the trim effect has also been investigated; Furthermore, the draft effect on the added resistance due to diffraction is further tuned and simplified. The derived formula uses only a few input, including only some ship dimensions to yield an estimation of the added resistance of ships in regular waves. Numerical results show that the added resistance of various ships in head seas at low speeds, as well as the added resistance of tankers in ballast condition and cruise ships, can be properly captured by the new formula. Hence, it meets the demand of fast examination of the minimum power; it can also be used in the early design stage of a ship for power estimation.

Evaluation of the Effect of Container Ship Characteristics on Added Resistance in Waves

“…Decreasing the speed for two knots can lead to an approximately 10% reduction in added resistance based on the results obtained using the Bretschneider wave energy spectrum. The obtained numerical results of the effect of ship speed, as well as pitch gyration radius on added resistance in regular waves, show similar trends as in [14]. .…”

“…The developed empirical method requires only main ship and wave characteristics as input values. The proposed method was extended and adapted for a wider speed range and variation of draft and trim at different loading conditions [14]. The authors analyzed the influence of the advancing speed, the pitch radius of gyration, the draft and the trim on the amplitude and position of the peak value of the added resistance in head waves.…”

Comparison of added resistance methods using digital twin and full-scale data

“…The effect of ship speed is included in the method. Different versions of this method are also available to calculate added resistance in arbitrary wave headings and for a low draft or ballast condition (Liu and Papanikolaou, 2019) but more details about the hull are required.…”

Establishing the Influence of Methanol Fuelled Power Propulsion and Energy Systems on Ship Design

“…Lastly, a unanimous trend in conversions and retrofits to methanol is to first lengthen the vessel to generate additional space [24], [34], [35]. This is rational as increasing the length can have a limited effect on the resistance [37]. However in most retrofit cases, they maintain the existing hull shape and explore alternative placement options for the additional methanol tanks [15], [30], [34].…”