The project Värdering av verkan, sårbarhet och risk (eng: Assessment of lethality, vulnerability and risk) is one of the projects within the research and development program Weapons and protection. The purpose of the project is to develop methods for conduction assessments of the lethality of weapons and the vulnerability of targets. Within the project, a target description of an example vessel has been under development. A military vessel is a complicated system consisting of a substantial amount of sub-systems and components. During the past year, the target description has been tested with a generic warhead in order to investigate how it works and what needs to be developed further. Access to a well-functioning target description of a vessel is an important basis for investigating and developing methods for assessment of lethality and vulnerability. A target description that is not classified, but still being based on a realistic vessel will make development of methods easier because it will be easier to share information. Two simple models for estimating lethality and vulnerability of vessels have been investigated. One already existing and documented method for estimating the blast effect, and one suggested similar model for estimating fragment effect. Compared to simulations using the tool AVAL the results looks reasonable. The model for estimating fragment effects is currently in a draft version and in need of being verified with simulations and tests. The simple models can only supply rough estimates of weapon effects, but in an early design stage where prerequisites change quickly they fill an important function. They make it possible to get an understanding of how the changing prerequisites affect lethality and vulnerability of a vessel.