VISIR^® [vi'zi:r] is a model for the computation of optimal nautical routes. In VISIR-I, the first version of the system, the optimization considers the sailing time, while the navigational safety is treated as a constraint.

VISIR-I considers medium and small motor vessels with a displacement hull. The model consists of three components: a processor of environmental fields, a ship model, and an optimization algorithm. VISIR-I employs significant wave height, wave spectrum peak period, and wave direction forecast fields from an operational implementation of the WaveWatch-III model in the Mediterranean Sea. The ship model in VISIR-I accounts for calm water and added wave resistance, making use of vessel principal particulars. Furthermore, the systems checks the optimal route for parametric roll, pure loss of stability and surfriding/broaching-to hazard conditions. The optimization algorithm is based on a graph search method with time-dependent edge weights. The algorithm is also able to suggest a voluntary ship speed reduction.

VISIR-I is coded in Matlab^® .

VISIR-I is free and open software under the terms of the GPL license, and is distributed from the page http://www.visir-model.net/ .

Contacts

Gianandrea Mannarini

References

• Mannarini, G., Pinardi, N., Coppini, G., Oddo, P., and Iafrati, A.: VISIR-I: small vessels – least-time nautical routes using wave forecasts, Geosci. Model Dev., 9, 1597-1625, doi:10.5194/gmd-9-1597-2016, 2016.