14 



to heart, by such promoters from the experience of the past. But it 

 IF a healthful sign that much more effort than formerly seems now 

 being devoted toward securing technically correct workmanship in 

 treatment, construction and inspection, with a realization that only 

 thus can the best methods do themselves justice. 



In preparing the statements which accompany the tabulated ser- 

 vice records for various classes of piles, which follow the special. re. 

 port of the Board of State Harbor Commissioners, presented herewith, 

 it has been endeavored not to repeat the information developed at 

 length in last year's report, except as becomes necessary for purposes 

 of intelligent comparison. In view, however, of the fact that this com- 

 mittee, by authority of your last year's meeting, has now embarked 

 upon a continuing program, it is felt that the service record tabula- 

 tions themselves should be cumulative, presenting from year to year 

 the total body of record which has been obtained for this region. The 

 tabulations herewith presented, accordingly incorporate last year's 

 data with that obtained this year. They also repeat the tabulated data 

 presented in the special report of the Harbor Commission, so as to 

 make it conveniently, available with respect to each separate class of 

 piles. A final summary, similar to that of last year, has also been, 

 stated, so as to keep up to date any modifications of conclusions which 

 may from time to time become necessary. 



SERVICE RECORDS FROM STRUCTURES OF THE BOARD OF 

 STATE HARBOR COMMISSIONERS AT SAN FRANCISCO 



The files of the Board of State Harbor Commissioners constitute a 

 forty years service record comprising almost all types of commercial 

 pile construction, which have been introduced in San Francisco Bay 

 during this period. 



The efforts of the early Boards were largely directed toward re- 

 piling existing structures and contain frequent references to the enor- 

 mous expense of these replacements. In this work piles with the bark 

 intact and unbroken appear to have been the standard type used, al- 

 though some methods of preservation such as "built up" piles and 

 coatings were attempted. In 1888, in the report of the Board to Gov- 

 ernor Waterman, the first reference is made toward the adoption of a 

 policy of preservation, as follows: 



"The Board has given much attention to the various meth- 

 ods for the preservation of piles and timber from the ravages 

 of teredo (#) and limnoria. The engineer of the Board is 



#Where Teredo is spoken of as present on the Pacific Coast in 

 engineering publications of former years, Xylotrya is undoubtedly to be 

 understood. There is no biological evidence of the presence of Teredo 

 in San Francisco Bay until the invasion of recent years. 



