Coefficient of Discharge of Freeing Port

It is needful in design of the freeing ports to know discharge coefficients of them. Results of experimental studies now conducted are as follows.1. The fundamental coefficients for full-sized ports (Fig. 1), standing and upright, are shown in Figs. 2-5.2. The coefficient, when ports, small-sized, are standing and upright, is approximately independent of arrangement of deck houses.3. If ports roll, the coefficient will be somewhat decreased at a high water-head and moderately increased at a low head, so long as the ports are situated on the both sides of a well. Of ports along side passages, this tendency will be feeble.4. Orbital motion of a ship does not affect so much to the coefficient.5. We can use in some allowance the coefficient for an uprightly standing port.6. Continuous ports on the both sides of a well, found on cargo ships etc., will discharge water between the top of the bulwark and the upper edge of the port within one period of rolling. A port along a side passage will show the same capacity, if it has an area required by the “Free-board Rule”.7. Deducing the size of port, the coefficient get larger.8. A slant port (Fig. 20), bored in an inclined plane inside a bulwark lest the port-door may open and patter with ship's rolling or by wind, proves some increment even in discharge.