The report gives a brief presentation of blast effects in confined volumes. In particular, blast effects in naval structures are discussed. Examples of typical structural damages and simple methods for assessment of blast effects are given. Further on, methods for calculations of shock and "quasi-static" pressure loading of complex (multiple compartment) structures are presented. Special attention is payed to rise of pressure in compartments adjacent to a specific "detonation compartment´. Ventilation effects to surrounding free air is also considered. Finally, blast collapse criteria for structure panels are briefly discussed.