Optimum Profile of BBDB
The optimum profile of BBDB is discussed to relate to the effect of the length, L, and the drafts, d1 and d2, in Fig. 1. Figures 9 and 10 show the calculation results of the optimum condition in which the load damping and the wavelength are tuned to obtain maximum efficiency. Figure 9 shows the effect of draft, d1 /B. The efficiency is higher as the draft becomes deeper. However, if the draft, d1 /B, is deeper than 1.0, the change of efficiency becomes
small. The load damping is smaller as the draft becomes deep. The wavelength ratio, /L, becomes longer as the length of BBDB,L/B, becomes shorter. Figure 10 shows the effect of draft, d2 /B.
The efficiency becomes lower as the draft, d2 /B, becomes deeper.Therefore the draft d2 is decided to become deeper than the wave height. Finally, we recommend the optimum configuration of BBDB, which is L/B=2.0, d1 /B=1.0, and d2 /B=0.2.