A R tool (SENSECO) has been developed in the BENTHIS project (task 5.1) to analyze economic consequences for fishing fleets or vessels of the adoption of new gears (or shift to alternative métier) in combination or substitution to the current gears (or métier). The tool adopts a microeconomic perspective. It performs static comparative analysis of economic performances under different conditions and assumptions of effort reallocation. It enables to analyze risk of gear change in terms of probability of being viable according to different criteria and to uncertainties parameters. It is also designed for exploration of economic impacts and economic incentives of alternative gear adoption according to expected CPUE, prices, or costs structure. The interactive interface enables real time variation of inputs and representation of impacts on outputs with opportunity for stakeholders consultation and expertise inclusion. The document is a guideline for the use of the SENSECO tool. It details the inputs, outputs, parameterization and possibilities of the model.