In order to investigate the effect of sinkage and trim on form factor, resistance tests were condducted on two sets of geometrically similar models with keeping their trim and sinkage constant.The results of these experiments show that sinkage and trim have important effects on form factor of resistance and that form factor is nearly constant independent of ship's speed if the trim and sinkage in her runs were kept constant.

No abstract

No abstract

This paper deals with the scale effect on the propeller and self-propulsion factors. Propeller efficiency increases gradually with the increase of Reynolds number. Even if the propeller open tests were conducted over so-called critical Reynolds number, their results will not show the exact characteristics of the actual propeller. Wake fraction will be calculated from the followiog formula, Where, A and B are constants to be determined for a ship form. Thrust deduction coefficient will be calculated from the following formula, where, v is ship's speed, u the additional velocity imparted to the fluid by the propeller and k a constant depending on the hull form and speed of a ship.

In order to obtain a reasonable ship-model correlation line, scale effect experiments were performedl on some ship forms in the tank of Transportation Technical Research Institute. This report deals with results of these tests, and presents a new conception for form factor of ship's, resistance by analysing the test results in this tank and those for the Lucy Ashton and Victory ship, models.