61 



berth along the quay walla and warehouses can he placed on a hll behind the wall. 

 The harbor structures are then largely independent of changes in ship lengths, they 

 can be built of permanent materials and can usually serve indefinitely. This type is 

 usually adopted in ri\er harbors, such as that at New Orleans. The Carcjuinez -Strait 

 waterfront is largeh- of this type. In this type, however, the berthing capacity of the 

 harbor is virtually limited to the length of the waterfront along its perimeter. This 

 limitation, together with other conditions, makes the tiuay t>pe impossible of applica- 

 tion in harbors sUch as that of San Francisco, where this type would gi\'e insufficient 

 berthing capacity. The pier type is then used, the piers projecting from the water- 

 front line usually for a distance sufficient ff)r the berthing of the maximum length 

 ship. In this type of harbor, changes in lengths and capacities of ships unitNoidably 

 in\'ol\e obsolescence because of relatively frequent changes in pier facilities to accf)m- 

 modate them. The following is extracted from a report made in 1919 by Mr. Jerome 

 Newman, then Chief Engineer of the Board of State Harbor Commissioners: 



"As evidence of the rapitlity of the changes that have taken place in ocean 

 transportation in the last few years and the constant need for new types and 

 larger dimensions for piers, the experience of San Francisco may be adduced. 

 Prior to 1909, the standard pier was 80 feet wide and 600 feet long; it became 

 necessary, on account of deterioration, to replace some of the older structures 

 and it was decided to build for future increase of traffic and to erect perma- 

 nent piers of sufficient size to handle it. The new piers were 130 feet to 140 

 feet wide and 650 feet to 700 feet long with 200-foot to 220-foot slip spaces as 

 against 150-foot to 200-foot slip spaces previously deemed ample. In 1912, 

 before commencing the construction of four new concrete piers, a large number 

 of shipping men were consulted and in accordance with their views the piers 

 were made 200 feet wide and 800 feet long with 250-foot slips. Two or three 

 months ago plans were prepared for a new improvement at the southerly end 

 of the waterfront invohing se\eral piers 235 feet in width by 1000 feet in 

 length with 300-foot slips. In other words, in ten years the demands of com- 

 merce have increased pier width by about 80 per cent, pier length by 50 per 

 cent, and slip width by 50 per cent; the structures thought ample at the begin- 

 ning of the ten year period have become inadequate but must remain in 

 service because they are too expensive to be torn down and the new idea of 

 size required cannot be adjusted to existing piers." 



Instances of changing conditions which have limited the life of structures can be 

 cited for every large harbor. Those which ha\'e occurred in San Francisco Bay furnish 

 a typical example. 



Chronological Outline of Development of S.\n Fr.\ncisco H.\rbor 

 Influencing Economic Life of M.\rine Structures 



Prior to 1847 Harbor undeveloped. 



1847 First waterfront line established. 



Waterfront property sold to public. 



1849 Construction of first wharves and reclamation of waterfront 



property started. 

 1849-1869 Freight transportation almost exclusi\'ely by ship. 



