Study on the Load Variation Coefficients based on the Model Test

Abstract

The new analysis method of sea trial data is required from 1st September, 2015. ISO15016:2015 requires to correct delivered power, revolution rate and even though the ship speed by the direct power method which differ from the conventionalsea trial analysis method. The method divides the reasons of correction into the resistance increase and the reduction of propulsive efficiency in trial. The efficiency decrease in trial can be obtained by the load variation coefficients, quantitatively.

But the guidelines or procedures still have arguments when it comes to perform the analysis of load variation test. Many of the hull form designers do not recognize the effects of the load variation coefficients when theyare used in direct power method.

In the present study, the series of load variation test (LVT) in various hull forms are performed. This paper describes the procedure that measure, perform the LVT and analyze the results. The load variation coefficients are calculated in each case. The analysis results of tests are compared with calculation which is based on assumption of increased resistance. The assumed range in calculation is employed from -10% to +20% of the estimatedtotal resistance in ideal condition. The effects of main dimensions, kinds of ship and the efficiencies in ideal condition are investigated in both the calculation and the test results.