196 OCEANOGRAPHY 1961 — PHASE 3 



other photograph here that is a little bigger. On the platform we 

 installed special columns, 1, 2, 3, and 4 feet in diameter, with instru- 

 mentation contained in segments, for measuring the force of waves 

 against these ])ilings. 



We ran this, as I say, for some 4 years and collected some 15,000 

 feet of records like the sample here. We recorded forces during 

 several hurricanes. 



In addition to forces, we also recorded wave heights and orbital 

 velocities in the water. 



The wave height staff originally was based on the Beach Erosion 

 Board design, but we found we had to make modifications to their 

 design, and we changed to another version which worked a little better. 



Here is a sample record from Hurricane Flossie in late September 

 of 1956. On this chart, these represent the wave heights. The largest 

 one on this record, I believe, was a 22-foot wave. 



The upper part of the chart here is an indication of the forces on 

 the different segments of the pilings. These are the higher ones. 

 Nothing hits them except where the waves are really high. When a 

 real big wave came along, we have recordings of the forces, like this. 

 Yie have recorded hurricanes with many feet of records, like this. 



This was done on a cost-sharing basis. We offered the data to the 

 members of the oil industry and to the Navy on a cost-sharing basis. 



The participants in this particular program were Shell, Humble, 

 and the U.S. Navy. This was set up in Bay Marchand in 30 feet of 

 water. It was closed down in 1958, and we felt we had acquired all 

 the data that was useful from this depth of water. The results were 

 such that we found our platforms had been overdesigned. We found 

 that some of the oil companies and other agencies have been under- 

 designed with some of their towers. 



The type of data that results, or the type of information that results, 

 from that data analysis is shown in this sample profile of a wave, here. 

 These contours represent the forces exerted on the pilings at various 

 depths. 



For example, for this 14- foot wave, the pressure exerted up here 

 near the top of the wave amounts to 120 pounds per square foot. 



An interesting point is that down underneath the trough, because 

 of the back flow, there is a back pressure in the opposite direction of 

 60 pounds per square foot, half as much as the slam you get from 

 the top of the wave. 



At the conclusion of this work, we felt that we needed to get some 

 additional data, and so we set up another project last summer at South 

 Timbalier, which is in 100 feet of water. These are 3-foot pilings, 

 but it is the same sort of thing. 



On this wave project II, we have to do it at different depths, to 

 extrapolate. Again, we have offered the data to anyone interested 

 on a cost-sharing basis. The total cost is divided by the number of 

 participants. So far. Shell Oil Co. has joined up. The Navy at first 

 told us no, but we understand very recently they have changed their 

 minds. We are happy to have them do so. 



So this is another area of oceanography in which we feel the indus- 

 try can make a contribution. 



We also feel, because of the strong economic incentives we have had 

 to do so, we have learned a great deal about how to anchor ships, 



