PART IV: WAVE DATA 



7. Wave and tide gages on the Shell Oil Company platform, 

 Vermilion 22, were being operated by CERC during Danny's passage through the 

 Gulf of Mexico. The location of Vermilion 22 latitude is 29°28.2' N, 

 longitude 92°33.0' W, and the water depth is about 9 m. At the point of clos- 

 est approach, the eye of Danny was within 10 miles of Vermilion 22. Figure 5 

 is the hydrograph of observed and predicted tides at the location of Vermil- 

 ion 22. Figure 6 is a plot of observed minus predicted water levels. 



8. Wave measurements were made using a self-contained, internal- 

 recording pressure gage. The wave data were spectrally processed via a Fast 

 Fourier Transform algorithm and corrected for depth attenuation effects ac- 

 cording to linear wave theory. Figure 7 is a plot of the significant wave 

 height for 13-17 August 1986, corresponding to the approximate time of passage 

 of Danny. The greatest significant wave height occurring during Danny's pas- 

 sage was 9.71 ft with a period at the spectral peak of 9.5 sec. Appendix A 

 contains plots of the wave spectra observed at 1030 on 14 August 1985 to 1030 

 on 16 August 1985. The spectra contained in Figures A2-A13 are characteristic 

 of the evolution of a storm-generated sea state. 



14 



