22 



servative methods, classed together as the "paint and batten" methods. That the 

 great expense involved in the construction of a creosoting plant, and in the process 

 itself, has been a primary factor in limiting its use is illustrated by the following 

 notation of the Harbor Board in 1890: "The Board has not yet felt justified in incur- 

 ring the expense of a costly creosoting plant without further experiments. To this 

 end, various preparations of asphaltuni, limestone, canvas, burlap, ship felt, etc., 

 have been thoroughly experimented with." Among such in 1889 the Fremont Street 

 wharf was built with piles protected by the "Key West Pile Armor," a paint and canvas 

 covering. In 1894, piles protected by the "Rood Process," known also as "Perfection 

 Piles," were installed on the San Francisco waterfront, and other installations were 

 made with the "Vulcan Pile Armor" and the "Paraffine Process." Experiments were 

 also made with other ideas such as the "Built-up Pile." 



In connection with the old Fremont Street wharf the "Cyrus Wakefield" incident 

 has received such attention in some quarters that it requires mention. In 1892, which 

 it will be seen was only three years after the wharf was built, the ship "C\tus Wake- 

 field" was moored to this wharf when, a storm arising unexpectedly, the ship towed 

 a portion of the structure out into the bay. A chronicler of the time states, "An 

 examination showed that the piles were entirely destroyed by teredo." — again showing 

 the early tendency to call all borers of the shipworm type "teredo," although the 

 destroyer of the Fremont Street wharf was almost certainly the giant shipworm, 

 Bankia selacea, at least insofar as the destruction was of shipworm origin and not the 

 much more easily observable work of the Linuwria. To the latter there is no reference 

 in the contemporary' accounts of the incident. 



The year 1895 saw the introduction of concrete as a substructure material, con- 

 crete being first used as a casing for wooden piles instead of itself as a primary- material 

 for piling fabrication. In that year were completed the foundations for the new Ferry 

 Building, in which clusters of untreated timber piles totalling about five thousand 

 two hundred were encased in rectangular concrete piers constructed in open coffer 

 dams. In 1896, the Pacific Street wharf. Pier 7 (present Pier 5) and the Folsom Street 

 wharf (Pier 12, removed in 1915), were built with substructure units consisting of 

 clusters of three untreated timber piles encased in concrete placed inside a cylindrical 

 shell of 1%-inch boiler plate, the cylinders extending from a point just below mud line 

 to the wharf level. Those in the former wharf are still serving after twenty-nine years. 



For many years, this and similar types of mechanical armor were considered the 

 final and permanent solution of the substructure problem. From the multitude of 

 unsound or inadequate methods and proposals for making wooden piles everlasting — 

 which then, as now, beset the user of piling — failures were inevitable. Moreover, there 

 was then obtained a current average life from creosoted piling of only ten years. These 

 results were due to lack of understanding of the reduction in efficiency and in life 

 wrought on superficial piling protections by storm and other abrasion, and on both 

 them and creosoted piles b>- injur\- from dogging and pike poles and b>' cutting and 

 framing after treatment. Thus chemical wood preservation was unduly discounted 

 and mechanical armors or shells of materials immune from borer attack and capable 

 of surviving the rigors of marine exposure were considered by the Harbor Board to 

 be the only positive protection for timber. While use of all types continued in varying 

 degrees, the mechanical armor received greatest fa\-or b>- the Board for a considerable 

 period from this time on. 



The Harbor Board's report for 1898, however, still contained the familiar state- 

 ment: "The preservation of piles and timber is the one overshadowing question in 

 the administration of waterfront affairs." In the same report the engineer of the Board 



