Coronado, California 



The XSP was tested at a site offshore from Coronado, Calif. 

 (Figure 13d). A total of 15 soundings were made with the XSP in the 

 20-foot mode on 31 October 1982. The XSP was deployed from the deck of 

 the NCEL Ocean Research Craft (ORC) (warping tug) with the crane 

 (Figure 6). This site was used by the Offshore Bulk Fuel Supply (OBFS) 

 to install a Single Point Mooring (SPM) buoy using four large drag- 

 embedment anchors. The locations of these anchors were marked with 

 bouys (Figure 22) and labeled North, South, East, and West. Three XSP 

 soundings were conducted at each of the four anchor marker buoys; two of 

 the three used jetting at a water flow rate of 50 gpm and a pressure of 

 50 psi. Three other soundings (numbers 13, 14, and 15) were taken in 

 the area probing for the cobble layer detected with a jet probe in 

 February 1981. The data were very consistent from sounding to sounding. 

 An example is provided in Figure 23. The stratigraphy developed from 

 the 15 soundings is shown in Figure 24. Those soundings conducted 

 without jetting reached 7 to 8 feet in depth. For three of the sites, 

 the soundings with jetting reached from 8-3/4 to 9-1/2 feet in depth. 

 At the East Buoy, however, refusal was met on one sounding at 5-1/4 feet 

 with jetting and at 7-1/2 feet for the remaining two soundings (one with 

 and one without jetting). Refusal may have been met at 5-1/4 feet due 

 to hitting a cobble layer or rock since, at the end of the testing, the 

 cone tip was found to be flattened. The last three soundings were done 

 to probe and map the area. One sounding was shoreward of the buoys 

 where refusal was met at 6-1/2 feet, and the other two were seaward of 

 the buoys where refusal was met at 9-1/2 feet. The results of these 

 soundings are similar to those of jet probing done at the same sites 

 (Figure 25). 



No problems were encountered in conducting these soundings. How- 

 ever, it is apparent that very dense sands or cobble layers cannot be 

 penetrated with the 10,000 pounds of thrust which can be developed by 

 the XSP. 



DISCUSSION 



In general, the XSP has shown itself to be a reliable piece of 

 equipment for gathering in-situ soil data. A total of 64 soundings were 

 performed, and the only major problem encountered was on the very first 

 sounding when the cone unit was broken off and lost. The XSP can be 

 handled easily if the support vessel has the proper amount of space and 

 lifting equipment. The easiest way to deploy the XSP is with a deck 

 crane (Figure 6). However, it was demonstrated during the tests at 

 Norton Sound that the XSP can be deployed from a horizontal position 

 when held by davits over the side of the ship (Figure 7). Successful 

 deployment and recovery of the XSP requires a stationary support vessel. 

 Deployment has been made in sea state 2, and it is anticipated that sea 

 state 3 is a limiting condition (depending on the support vessel and 

 handling procedures). 



33 



