The blackboard approach has been successfully used in a variety of domains. A typical problem-solving cycle consists of deliberation, scheduling, and execution steps. This paper presents a scheduling approach that uses the mathematically well-founded framework of Petri Nets as an environment model to represent the scheduling context. The paper extends the classical Petri Nets model in various ways and shows their decision making and tutoring applications in the test-bed domain of ship damage control. The use of a scheduler based on Extended Petri Nets resulted in 21 of 160 ships being lost in an immersive simulated environment. This is a 46% improvement over subject experts where 39 ships were lost.