Improvement of Statistical Estimation of Ship Performance in Actual Seas by Normalization of Data Unevenness Using Cluster Analysis

2020 ◽  
pp. 878-898
Author(s):  
Munehiko Minoura ◽  
Takaaki Hanaki ◽  
Taito Nanjo
Keyword(s):  
Cluster Analysis ◽  
Statistical Estimation ◽  
Ship Performance ◽  
Actual Seas

Development of a Ship Performance Simulator in Actual Seas

2015 ◽  
Author(s):  
Masaru Tsujimoto ◽  
Naoto Sogihara ◽  
Mariko Kuroda ◽  
Akiko Sakurada
Keyword(s):  
Energy Efficiency ◽  
Fuel Consumption ◽  
Hydrodynamic Performance ◽  
Wave Forces ◽  
Ship Hydrodynamic ◽  
Main Engine ◽  
Ship Performance ◽  
Actual Seas ◽  
Ship Speed ◽  
Drift Forces

Greenhouse gas shall be reduced from shipping sector. For that purpose the regulation of EEDI (energy efficiency design index for new ships) and SEEMP (ship energy efficiency management plan) were entry into force from 2013. In order to improve energy efficiency of ships in service it is necessary to predict the fuel consumption in actual seas. In order to reduce GHG emission from ships, a Vessel Performance Simulator in Actual Seas has been developed. It simulates ship speed and fuel consumption at steady condition by using weather data and designated engine revolution. Physical models for hull, propeller, rudder and engine are used in the simulator. Especially steady wave forces, wind forces, drift forces, steering forces and engine/governor model are important factor for the estimation. The fuel consumption should be evaluated combined the ship hydrodynamic performance with the engine/governor characteristics. Considering the external forces by winds and waves, the operation point of the main engine is important for the estimation, since the torque limit and the other limit of the engine/governor are affected to the ship hydrodynamic performance. To prevent the increase of fuel consumption in service, the engine control system by the Fuel Index has been applied to present ships. In rough weather condition the revolution of the main engine is reduced to lower revolution by the Fuel Index limit. It causes the large decrease of ship speed but reduces the fuel consumption due to reduction of engine revolution. Using the simulator the navigation performance of a container ship, a RoRo vehicle carrier and a bulk carrier is simulated along the route. In this paper following contents are discussed; 1) evaluation of the physical model; steady wave forces, wind forces, drift forces, steering forces and engine/governor model, 2) simulation and validation of the physical model by tank tests and on-board measurements and 3) effectiveness of the ship performance simulator for GHG reduction.

Detailed Study on the Behavior of Ships in Very Short Waves

2020 ◽  
Author(s):  
Saori Yokota ◽  
Mariko Kuroda ◽  
Ryohei Fukasawa ◽  
Hiroki Ohba ◽  
Masaru Tsujimoto
Keyword(s):  
Sensitivity Analysis ◽  
Fuel Consumption ◽  
Added Resistance ◽  
Regular Waves ◽  
Short Waves ◽  
Added Resistance In Waves ◽  
Tank Test ◽  
Ship Performance ◽  
Ship Operation ◽  
Actual Seas

Abstract Considering the sea conditions in which a large ship encountered in operation, the ship’s behavior in very short waves is important. However, the evaluation of the ship performance in very short waves was not enough validated by tank tests. Because it is difficult to generate waves with enough accuracy due to the performance of the wave generator. In this paper, it is shown that tank tests of added resistance in the regular waves including the very short waves are conducted in the Actual Sea Model Basin at National Maritime Research Institute, MPAT for DTC container ship and accurate results are obtained. The test results are compared with the benchmarks published by SHOPERA (Energy Efficient Safe SHip OPERAtion). In addition, three curves of the added resistance in the regular waves based on the results of the tank test are compared and the sensitivity analysis of energy efficiency is discussed. In the sensitivity analysis, the performance simulator for ships in actual seas (VESTA) is used, and a comparison is carried out for the fuel consumption calculated from the frequency response of each added resistance in waves. As a result, it is found that the tendency in added resistance in very short waves affects the fuel consumption and the decrease of ship speed.

Wind Loads Simulator for Free-Running Model Ship Test

2017 ◽  
Author(s):  
Yoshiaki Tsukada ◽  
Ryosuke Suzuki ◽  
Michio Ueno
Keyword(s):  
Model Tests ◽  
Wind Loads ◽  
Control Procedure ◽  
Motion Data ◽  
Tank Test ◽  
Free Running ◽  
Using Data ◽  
And Control ◽  
Ship Performance ◽  
Actual Seas

The authors have developed a wind loads simulator (WiLS) that enables us to carry out free-running model tests for investigating wind effects on ship performance. WiLS provides a free-running model ship with simulated wind loads taking account of supposed true wind speed and direction, and instantaneous model ship speed, drift angle, and heading angle. It does not generate environmental wind but exerts forces and moment on a model ship using three pairs of duct fans. A control PC calculates time varying longitudinal and lateral wind forces and yaw moment using wind loads coefficients estimated beforehand and ship motion data, and distribute them to the three pairs of duct fans. Feedback control ensures the intended wind loads using data from load cells on which the duct fans are mounted and those from accelerometers for correcting inertia forces of the duct fans. This paper reports the concept, configuration, and control procedure of WiLS, and presents tank test data, which confirms effectiveness and usefulness of WiLS as a device in free-running model tests to evaluate ship performance at actual seas.

Evaluation of Service Performances of Liquefied Natural Gas Carriers in Actual Seas

2014 ◽  
Vol 69 (7) ◽  
Author(s):  
Mohd Azuwan Ahmad ◽  
Faizul Amri Adnan
Keyword(s):  
Natural Gas ◽  
Evaluation Method ◽  
Wind Wave ◽  
Liquefied Natural Gas ◽  
Service Performance ◽  
Ocean Current ◽  
Loading Patterns ◽  
Ship Performance ◽  
Actual Seas ◽  
Insight Into

Ship performance in actual seas represents the true performance of the ship throughout the service life and is affected by the combination of various conditions i.e. environments, loading patterns and ship conditions. Environmental conditions of wind, wave, swell and ocean current are chaotic and stochastic in nature. Loading condition may vary in draft, trim and motions in each voyage. Ship condition is susceptible to hull and propeller fouled over years. This paper provides insight into the service performance of Liquefied Natural Gas Carriers (LNGC) in actual seas derived from post-mortem on years of voyage’s noon report collections. Evaluation method of service performance will be proposed and benefits that can be gained from such analysis will be discussed.

scholarly journals A Numerical Model of Speed - Revolution - Power Relation for the Evaluation of Ship Performance in Actual Seas

2017 ◽  
Vol 25 (0) ◽  
pp. 39-46 ◽  
Author(s):  
Akiko Sakurada ◽  
Mariko Kuroda ◽  
Masaru Tsujimoto ◽  
Yoshihiko Sugimoto ◽  
Ken Hasegawa
Keyword(s):  
Numerical Model ◽  
Power Relation ◽  
Ship Performance ◽  
Actual Seas

Development of a Weather Adaptive Navigation System Considering Ship Performance in Actual Seas

2006 ◽  
Author(s):  
Masaru Tsujimoto ◽  
Katsuji Tanizawa
Keyword(s):  
Fuel Consumption ◽  
Navigation System ◽  
Weather Forecast ◽  
Weather Data ◽  
Vertical Acceleration ◽  
Augmented Lagrange Multiplier ◽  
Ship Performance ◽  
Actual Seas ◽  
Ship Safety ◽  
Augmented Lagrange Multiplier Method

Aiming to reduce fuel consumption and CO2 emission a new navigation system called WAN has been developed. The system provides optimum route and engine revolution with constraints of schedule and seakeeping criteria. In this paper, simulations of a container liner on transpacific route are demonstrated using WAN. Weather data used here are composed of 8 items; significant height, period and peak direction of wind wave, significant height, period and peak direction of swell, and mean speed and direction of wind. Ship responses; i.e. ship speed, fuel consumption and vertical acceleration at F.P., are calculated based upon the enhanced unified theory. To optimize route and engine revolution the augmented Lagrange multiplier method is applied. The objective function of minimization is fuel consumption with constraints of the schedule and the service limit. From the simulations, the effectiveness of WAN resulted very high and it is shown that the reduction of the fuel becomes 26.1% on average. Concerning the schedule keeping, accuracy of weather forecast must be examined. The influence on the system is evaluated using two kinds of weather data; one is a forecast received at departure and the other is the dataset extracted from the sequential forecasts of every 24 hours. From the simulations it is found that the fluctuation of fuel consumption due to updating the weather forecast is much smaller than the reduction of the fuel by WAN. However, from the viewpoint of ship safety, it is necessary to execute the system again whenever the weather forecast updated.

Cluster analysis for large data sets: applications to individual aerosol particles from the mid-pacific

1992 ◽  
Vol 50 (2) ◽  
pp. 1488-1489
Author(s):  
Thomas W. Shattuck ◽  
James R. Anderson ◽  
Neil W. Tindale ◽  
Peter R. Buseck
Keyword(s):  
Cluster Analysis ◽  
Chemical Reactivity ◽  
Large Data ◽  
Large Data Sets ◽  
Particle Analysis ◽  
Data Sets ◽  
Halogen Chemistry ◽  
Complete Study ◽  
Components Analysis ◽  
Automated Scanning

Individual particle analysis involves the study of tens of thousands of particles using automated scanning electron microscopy and elemental analysis by energy-dispersive, x-ray emission spectroscopy (EDS). EDS produces large data sets that must be analyzed using multi-variate statistical techniques. A complete study uses cluster analysis, discriminant analysis, and factor or principal components analysis (PCA). The three techniques are used in the study of particles sampled during the FeLine cruise to the mid-Pacific ocean in the summer of 1990. The mid-Pacific aerosol provides information on long range particle transport, iron deposition, sea salt ageing, and halogen chemistry.Aerosol particle data sets suffer from a number of difficulties for pattern recognition using cluster analysis. There is a great disparity in the number of observations per cluster and the range of the variables in each cluster. The variables are not normally distributed, they are subject to considerable experimental error, and many values are zero, because of finite detection limits. Many of the clusters show considerable overlap, because of natural variability, agglomeration, and chemical reactivity.

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