From the above sources, a list of 81 potential sites was compiled. For 

 each site, an attempt was made to contact the FB operator by an introductory 

 letter. Three leads resulted in deadends with the contacts listed as unknown. 

 Thirty-one did not respond to the letter, making their status unclear as to 

 whether an FB was ever installed. Nine responded that while an FB was once 

 planned, it was never built. Finally, 38 answered affirmatively that an FB 

 was, at some point in time, in operation; these operators were then sent sur- 

 vey questionnaires. A total of 21 operators completed the survey. The sur- 

 vey results of the field experiences of the 16 FTB sites and the 5 FB sites 

 are given in Appendixes A and B, respectively. Appendix C contains the ques- 

 tionnaire sent out to the FB operators. Appendix D lists the 17 known sites 

 for which a survey was not completed. Appendix E lists the 31 unconfirmed 

 sites which may or may not have had an FB in operation. 



Once the surveys were in hand, the operator's information was cross- 

 checked against any other data known for the site. Typically, this other in- 

 formation was available through the Corps permits, the Hydrotechnology, Ltd. 

 files or site visits conducted by Mr. Ross or the staff of MRM. Where con- 

 flicting data existed, the respondents were contacted directly to resolve 

 any inconsistencies. When satisfied with the degree of detail in the site 

 data, the information was transferred to narrative summary sheets which are 

 included in the body of this report. 



The final step was to perform a simple qualitative engineering analysis 

 of each FB project and suggest the causes for any problems arising and the 

 actions needed for their successful resolution. To conduct this analysis, 

 MRM relied heavily on Mr. Ross' extensive experiences since 1974 with FTBs 

 and the staff's own coastal engineering expertise. Obviously, it is the 

 intent of this report, based on the cumulative field experiences of many FB 

 operators, to provide this capability to analyze and refine FB designs to 

 future users. 



2. Reliability of Findings . 



For the most part, there is no reason to suspect that some of the values 

 assigned by the operators to the physical parameters of the FB systems should 

 be in question. Elements such as physical dimensions, construction materials, 

 and mooring configuration are easily measured and reported. However, certain 

 types of information, the most important of which are listed below, are much 

 more difficult to accurately ascertain. 



a. Site Conditions . Even with proper instrumentation, measuring wave 

 height, length, and direction of propagation is a complicated undertaking. 

 In many cases, the survey was probably the first time an operator had to face 

 the quantitative question of what conditions exist off the site. It is be- 

 lieved that in most instances, the operators provided reasonably accurate 

 answers for storm wave height and direction, for these parameters are the 

 simplest to measure--requiring but two fixed reference points. However, most 

 reported wavelengths appeared erroneous, since sea conditions often seem ex- 

 aggerated to untrained observers. To compensate, MRM provided an estimated 

 wavelength based on the reported fetch, windspeed, water depth, and outside 

 wave height. However, even this empirical answer is questionable and should 

 be viewed suspectly. 



