Analyses of electronic equipment on board Danish trawlers and gillnetters show that newer, larger vessels have a significantly higher “technological level” than older, smaller vessels. A hypothesis of linkage between fish-finding and navigation technology on board and standard vessel characteristics was tested based on the definition of a technological index. Using a proportional odds model, vessel length accounted for most of the variation in technological level on board, with odds of 1.17 (95% confidence interval: 1.16–1.18) of a higher index value for each increase in vessel length of 1 m. Vessel age was also significantly correlated with index values. In considering the technological index as an indicator of fishing power, the results have important implications for capacity-reduction schemes intended to reduce harvest pressure on fish stocks. In the course of such structural management plans, older, smaller vessels of a fleet are often replaced with newer, larger vessels within a fixed or reduced nominal capacity limit (e.g. total fleet tonnage), but according to the findings presented, nominal capacity reduction in fleet level may be undermined by increases in individual vessel fishing power.