In order to fully understand the diagram, some concepts must be clarified within the scope of the
presented system. Ship compartments are in this case watertight spaces in the interior of the hull
connected by watertight accesses like doors and hatches. The state of an access may be opened or
closed allowing or not the propagation of the water through the ship compartments. Damages in this
case are typically holes in the hull caused by collisions or groundings that will trigger the flooding of a
ship compartment. The damage information is the dimensions, shape and location of the holes, which
will influence the flooding progression. The concept of ship condition in this scope defines the state of
all accesses, levels of water in compartments and damages’ characteristics, while the ship status refers
to the stability condition and is defined by the draft, trim and heel. Finally, the virtual and real ship
refer to the ship in the simulation system and to the ship in the real world respectively. Excluding the
starting time of the simulation, the virtual and real ship conditions and status do not have to, an d will
not be coincident most of the time.
In a real situation, the system is typically installed in the Damage Control Room for the case of
military vessels or in the navigation bridge for other types of ships. In order for the system to work
with its full capabilities, a detection system composed by sensors at the compartments and watertight
accesses such as doors and hatches must also be installed in the ship.
As depicted in Figure 1, three main elements are considered in the real ship: the compartments, the
accesses between compartments and the damages. In a flooding situation, watertight compartments
and accesses between them are the most significant elements for the progression of the flood. Sensors
are installed to detect the water level inside each compartment and the current of state of watertight
doors, hatches or valves. In order to run the simulation, ship damages like holes in the hull, must also
be identified and inputted into the system. For this case, real-time sensors like the ones mentioned
before, are not able to provide damage information such as dimension, shape or location of the holes.
This can only be achieved by camera surveillance or by visual inspection. Sensors will send the
current ship condition and status in real-time to the simulation system. Information collected by the
sensors is sent to the simulation system and updated accordingly in real-time. However, damage
information, either recorded by cameras or provided by emergency crew members must be inputted
manually by the user. Therefore, the Virtual Environment must provide quick and efficient methods to
input damage information into the simulation system. The ship status an d condition, including the
damage information, is the required/sufficient information to start the simulation.
Within the software system, two main modules must exist: the Virtual Environment and the
Progressive Flooding. The exchange of data between the s imulation system and external elements
such as sensors, display devices or the user, is achieved uniquely through the Virtual Environment. It
provides all the necessary features to setup, start, control and visualize in real-time the course of the
simulation. A virtual model of the ship containing all the compartments with accesses and their
underlying topology as defined in the flooding mathematical model, is built and connected to the
progressive flooding algorithm. According to the input data provided by the Virtual Environment,
which includes the ship status computed in the previous simulation step, plus any updates to the ship
condition, the flooding algorithm computes and sends the new ship status to the Virtual Environment.