The boat has a ventilation device for ventilating interior of the boat, and a carbondioxide absorption device (2) with absorption containers (8 power I - 8 power IV) filled with absorption mediums i.e. hydroxides. The containers are arranged in line strands (6 power I - 6 power IV) of the ventilation device parallel to each other and shifted in a position in which ventilation air flows in the containers. The containers are sealed at an input-side and an output-side with a check valve (12) in a gas-tight manner. A control device controls opening and/or closing of the check valve.
