On a Calculation of Decrease of Ship Speed in Actual Seas

Abstract

Reduction of green house gas from international shipping shall be put forward. For the reduction, it is important to promote to introduce ships of high energy efficiency to the shipping market. In actual seas a ship decreases her speed not only the deterioration and fouling effect but also by natural forces such as winds and waves. By design technique, ship propulsive performance in actual seas is able to improve. Hence ship propulsive performance in actual seas has much scope to improve the energy efficiency.We present a calculation method of decrease of ship speed in actual seas. From the point of accuracy, the method involves correction for added resistance in short waves combined with a tank test. As examples three kind of ship; a container ship, a car carrier and a bulk carrier are examined and the components of external forces acting on the ship are discussed.

Systems analysis for deployment of internet of things (IoT) in the maritime industry

“…2. The ship speed reduction rate is calculated by a method proposed by [21]. Based on the reduction rate, the ship performance model is modified, and ΔSFOC is obtained.…”

Estimasi Performa Sistem Propulsi Pada Kapal Dengan Tipe Controllable Pitch Propeller

“…Untuk menyelesaikan permasalahan tersebut, perhitungan performa permesinan kapal dapat dilakukan secara analitis dengan melakukan perhitungan yang telah dilakukan peneliti lain dengan mengintegrasikan nilai dari berbagai hambatan yang dialami oleh kapal (angin, gelombang dan added resistance) (Tsujimoto et al, 2009;Zhao et al, 2015) dan estimasi daya yang dilakukan dengan memprediksi penurunan kecepatan sehingga mendapatkan nilai aktual dari daya mesin (Chuang dan Steen, 2011). Permasalahan selanjutnya akan muncul, jika jenis dari propeller suatu kapal adalah Controllable Pitch Propeller (CPP).…”

Onboard Measurement for a Container Ship in view of Container Load Condition

“…For the verification of the calculation method 1) of speed in actual seas, available data under the condition close to the calculation condition is extracted. In the calculation, the added resistance in waves is calculated by the hybrid calculation method 1) , the wind resistance is calculated by the Fujiwara's method 5), 8) , and the ship speed is obtained from the equilibrium equation. The calculation condition of the object ship is determined from the actual operational condition, that is 50% of MCR output on the designed full load condition ( 12 m draft ) and 45% of MCR output on the operational condition #1 (10 m draft).…”

“…In National Maritime Research Institute, a calculation method for ship speed in actual seas on a constant engine output has been developed 1) . The method uses a parameter derived from a simple tank test in waves, and enables to calculate added resistance due to waves with accuracy, which is one of major components of external forces acted on a ship hull in actual seas.…”