(c) If a more uniform distribution of wicking agent and primer had been 

 achieved, and the weathered oil had been susceptible to being burned, there 

 is reason to believe the ignition technique used would have been adequate. 



2.2.8 "Tar Ball" Reports 



On March 10, large tar balls began coming ashore on the southwest coast 

 of Nantucket Island. The balls were reportedly as much as a foot in diam- 

 eter; one, found on the eastern shore of Nantucket, weighed 70 pounds. The 

 material was deposited in a widely scattered pattern around centers about 100 

 feet apart. The tar was relatively fresh and contained no entrained sand or 

 other materials, suggesting that it had been floating and weathering after a 

 recent spill. 



Samples of the tar were given to Dr. John Farrington at WHOI for chem- 

 ical analysis. This work may be able to document the tar as being derived 

 from crude or refined petroleum; but it will not be able to establish con- 

 clusively whether the tar originated with the Argo Mevahant spill or with 

 another No. 6 fuel oil spill. 



2.3 Oil Trajectory Modeling Efforts 



Several independent modeling efforts were made to explore the implica- 

 tions of the Argo Merchant oil spill, some of which were provided the Federal 

 On-Scene Coordinator (OSC) for operational forecasting of the oil distribu- 

 tion. Cmdr. C. Morgan, an oceanographer, who was assigned to the OSC Staff 

 from the USCG Oceanographic Unit, played a principal role in incorporating 

 the efforts made available on scene into operation decision making. Other 

 efforts whose results were not forwarded to the OCS are included for compar- 

 ison and completeness. The six modeling efforts presented include "forecast" 

 trajectories based on predicted or actual winds and currents, as well as 

 "risk" trajectories which used climatological or historical winds and cur- 

 rents. Validation efforts by the contributor included comparison of forecast 

 trajectories with observed oil location as well as confirmation of climatol- 

 ogical wind pattern with observed winds. 



All the models incorporated vector addition of the forces that moved the 

 oil, which included winds, tides, and semipermanent currents. In general, 

 differences in the model outputs are attributable to: (1) different sources 

 of winds, whether measured, forecasted, or climatological; (2) different 

 sources of currents, and (3) differences in how wind drift, both surface 

 water and oil/water differential, was included. Table 2-5 summarizes the 

 input data and the major techniques used for the six models or an aid for 

 comparison. 



All the models predicted that the oil on the surface would be moved off- 

 shore under the influence of the prevailing westerly winds. Since the actual 

 winds were more towards the east than the climatologically predicted south- 

 east, the forecast models appear more accurate in predicting the movement of 

 the surface oil than the risk models. Additionally, those models which used 

 tidal or net tidal currents rather than mean or climatological currents are 



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