23. Plates 15-17 are the significant wave heights at each of the plat- 
forms during the storm passage. The wave data were acquired by using a sub- 
surface pressure sensor and a self-contained, internally recording digital 
data logger. The pressure records were cosine tapered and spectrally analyzed 
by means of a Fast Fourier Transform algorithm. Each spectral component was 
then corrected for depth attenuation by using linear-wave theory and the 
periodogram block averaged resulting in a spectrum with 32 equivalent degrees 
of freedom. Spectral plots of the wave data acquired during Alicia's passage 
are contained in Appendix A. 
24. Plates 18-20 are hydrographs obtained at the Shell platforms for 
the month of August 1983. The dates of Alicia's passage through the Gulf of 
Mexico were approximately 15-20 August 1983. The hydrograph obtained at 
Vermillion 22 shows a departure of about 1.25 ft from the expected tide range 
on 17 and 18 August. Hydrographs obtained at Eugene Island and Bay Marchand 
show almost no departures from the expected tide. 
14 
