Napa has developed a tool that exceeds the traditional expectations set for an onboard decision support system and can be used to evaluate the progress of flooding inside the ship in real time. The results reflect the ship's condition on a time scale and thus provide support for decision-making onboard the vessel.

Preplanning (of the loading condition) is a key element of accident prevention. Before sailing, it is very important to check that the yacht meets the intact and damage stability requirements. Onboard-NAPA makes it quick and easy to check compatibility with rules and regulations. In addition, other requirements for yachts often need to be taken into account even though there is no specific regulation. The onboard decision support system provides a good overview of the yacht's stability at any given time.

One of the main advantages is that the system allows the captain to investigate a damage scenario of any kind in advance, in order to determine how well the yacht would cope with different damage conditions, thereby increasing overall awareness. This also reveals possible risks before departure and helps to prevent them.

Should damage to the yacht occur - if there is a breach, collision or grounding - it is essential to know how severe the damage is and how far the flooding might escalate. Such a situation could raise the question: Will the yacht be lost? The yacht and the people onboard would need to be prepared for the worst. 

First, it is essential to know how badly the yacht is damaged. Together with proper flooding sensors, Onboard-NAPA provides vital information about flooding. Accurate level sensors, which are used to calculate the flood water rate, enable better prediction. 

The second step is to determine what can be done to prevent further flooding. The Onboard-NAPA DFC (Decision Support for Flooding Control) concept also includes Advisory Cards, a feature for immediate actions to secure compartment from progressive flooding. The Advisory Cards include relevant subsystems with different options. The instructions also include digital pictures of these subsystems. Advisory Cards can also be connected to the CCTV system to provide live video of the compartments.

Finally the captain will want to determine the outcome of the current flooding. The flooding rates obtained from the sensors are the initial information for the flooding simulation. Alternatively, the user may also provide information about the damage manually. Using the flooding rate and information about the floating position, the damage opening can be calculated on the basis of the 3D model. 

The Onboard-NAPA flooding simulation tool calculates the progressive flooding through different openings inside the yacht. The openings are included in the 3D model with specific characteristics, e.g. area, the discharge coefficient etc. Openings, such as different types of doors, also have certain characteristics indicating leakage and collapsing pressure. These characteristics have been individually assigned for each opening. The collapsing and leaking pressures are currently based on IMO SLF 47/INF.6. (However, Napa Ltd is currently taking part in the EU FLOODSTAND project where, for example, specific door characteristics are being studied and measured in full-scale tests).

The flooding is simulated until the yacht reaches equilibrium or the yacht capsizes. The simulation results are presented in a simple visual format. Trend displays show how list, trim, draft and displacement change over time. Time to capsize, opening submersion, door collapse etc. are all indicated clearly. It is important that the whole flooding process is visualised in both 2D and 3D in order to understand how the flood water progresses inside the complex spaces and compartments.

Once the flooding has been analysed and the outcome of the analysis reveals no immediate threat of losing the yacht, mitigating actions can be investigated. The mitigating actions can be performed in several different ways. The results of simulations can give clear indications of how to cope with the damage in question: Whether to abandon the yacht or to carry out certain countermeasures may seem obvious, but it must be remembered that the captain always makes the final decision. "Onboard-NAPA is a decision support system, NOT a decision-making system."

Since NAPA software is used at many yards, by consultants and at most classification societies, it is also used for emergency response (ER) services. The compatible loading condition and damage condition files are fast and easy to transfer from yacht to shore, enabling rapid and better emergency response.

The Onboard-NAPA damage stability system is specifically designed for onboard use, but it can easily be used as an emergency response tool ashore as well. The office version, which is an exact copy of the system onboard, can be installed on any PC or laptop in use by a DPA (Designated Person Ashore). Once the onboard system is connected to the same network, the loading condition can be transferred automatically for ER use