approximately with the available apparatus. Although the viscosity change 

 of about three-fold was larger than that of the distillate fuels, this 

 change again was equivalent to only a 12°C (or 20°F) temperature change 

 when plotted on a viscosity-temperature chart. However, this change 

 occurred with a smaller evaporation loss. Also, this was the viscosity 

 of the recovered NSFO, and the viscosity of the ''mousse'' might have 

 been higher. 



CONCLUSIONS 



1 . Navy distillate fuels are relatively persistent oils and do not 

 evaporate rapidly in thick films. 



2. Initial weathering of thick films of spilled Navy distillate fuel 

 should not materially change the amount of oil that must be salvaged. 



In simulated weathering of 5 -mm fuel oil films on salt water for one week, 

 the Navy distillate fuels left residues of 75% to 90% of the original 

 oils. 



3. Initial weathering of thick films of spilled Navy distillate fuel 

 should not materially change the handling characteristics of the oils. 

 Simulated weathering of 5-mm fuel oil films on salt water produced 

 small increases in viscosity and small changes in boiling range. 



4. Very thin films of Navy distillate fuel will evaporate much more 

 rapidly than Navy special fuel oil. Navy distillate fuels exposed in 

 0.1 -mm films under a current of air for one week, left residues of 

 about 5%, whereas the Navy special fuel oil left a 65% residue. 



5. The weathering characteristics of distillate fuels can be correlated 

 with their gas chromatographic behavior. Oils with greater portions of 

 low boiling components (below about C-jc) will have higher Initial losses, 

 and oils with greater portions of high boiling components (above about 

 C20) will leave greater residues. 



6. In simulated laboratory weathering, the persistent emulsion formed 

 with Navy special fuel oil is not formed with Navy distillate fuel. 



ACKNOWLEDGMENT 



The assistance of Mr. C. W. Mathews in the experimental work is 

 appreciated. 



REFERENCES 



1. S. A. Berridge, R. H. Dean, R. G. Fallows, and A. Fish. "The 

 properties of persistent oils at sea,'' in Scientific aspects of 



12 



