Progressive Speed Trial
The progressive speed trial to be carried out to determine the corresponding values of speed, RPM and BHP by four double runs, namely at 50%, 70%, 90% and 100% of MCR of the main engine. The trial speed shall be measured by DGPS.
Test Condition
Weather and Sea Condition
The speed trial to be carried out in weather condition with wind of not over 4 Beaufort scale as far as practicable and possible for the Yard’s building schedule.
The depth of water is more than 75.0m in general, but if the sea condition of deep water is too bad to perform the progressive speed trial when sea trial, the test to be done at the shallow water about 35m under the owner acceptance.
Ship Condition
The speed trial to be carried out on the design mean draught 11.00m, even keel or with small stern trim, and the main engine power set in four points about 50%, 70%,90% and 100% of MCR respectively.
Test Preparation
Prior to speed trial, the vessel’s drafts at fore/amidships/aft, the specific gravity and temperature of sea water, air temperature, wind direction to be measured and recorded by Yard together with Owner’s Supervisor and Regulation body’s surveyor in test area.
The course of speed trial to be with auxiliary navigating and measuring distances, and the course direction is head tide/down tide according to the recorded tide direction. In order to achieve a steady speed in speed measuring, the voyage distances of auxiliary navigating and measuring are not less than 2.0 nm.
Speed Trial
The speed trial to begin after the trial condition confirmed. Total four double runs to be carried out, one double run (to and fro) for one main engine power. Total four points of main engine power as Table below as example.
If the propeller can’t run to 131 rpm when main engine reach 100%MCR, 100%MCR to be used.
During the speed measuring, the deviation of vessel from specified course to be no more than 2° and the operating angle of steering gear is not greater then + or – 5°.
Measurement
In each run, speed to be measured by DGPS, and the powers and rotary speeds to be measured by shaft measuring equipment.
Results
The measured results of trial speed shall be corrected to the value under the condition with no wind and no current. The corrected results to be submitted to Owner for signing.
Reference: Speed Trial Procedure