Shiptrack occurrence is restricted to a narrow range of environmental conditions and ship operating characteristics. Under environmental conditions favorable for shiptrack formation, not all vessels produce a track. Shiptrack producing diesel vessels are distinguished from non-shiptrack producing diesel vessels by a 17.7 percent higher rate of fuel use, 8.8 percent larger power plant size, and one knot higher transit speed. T-tests comparing these two populations indicate that power/transit speed, powerfuel/speed, powerfuel, tonnage/fuel use, power/hull cross-section, transit speed, power plant size and rate of fuel use are tactically distinct (greater than 60% confidence level). These parameters and ratios of parameters may be useful in predicting the occurrence and non-occurrence of shiptracks.