# Fuzzy Logic in Selection of Maritime Search and Rescue Units
## 1 Introduction  
Sea transport and shipping are vulnerable to many risks, such as fire, collision, grounding, flooding, cargo shifting, man overboard, etc. In spite of introducing new safety rules and standards, accidents at sea are still common. According to the data published by the European Maritime Safety Agency [1], in 2014-2019, as many as 19,414 casualties and incidents occurred on ships flying a flag of one of the EU Member States within the EU Member States' territorial sea or internal waters (as defined in UNCLOS), resulting in 496 deaths and 6210 injuries. In distress, when the safety of the ship or its crew and/or passengers are in danger, abandonment of the ship is inevitable. Survival in the water or on-board a lifeboat or life raft is challenging, with hypothermia and drowning being the most common causes of death. A quick and efficient search and rescue (SAR) operation can prevent a disaster or at least increase the chances of survival. SAR operations are organised and carried out by a Rescue Coordination Centre (RCC) or another vessel in the vicinity. Crucial decisions are made by the SAR coordinator, and their assessment of the situation largely determines the success or failure of the operation. One of the decisions made at the stage of planning a SAR operation is the selection of vessels fit for the task [2]. Specialised search and rescue as well as civilian vessels can participate in an SAR operation. Specialised vessels are multifunctional, well equipped, and manned with a qualified crew. Varied technical and operational parameters of civilian vessels (e.g., cargo, passenger, fishing, leisure, research ships) either increase or reduce their potential for carrying out search and rescue tasks, being defined by the intended use of the ship, its structure, manoeuvrability, equipment, and experience of the crew. Suitability of vessels for an SAR operation is assessed based on a variety of criteria. The most important ones are speed, seaworthiness, range of operation, availability of detection equipment, equipment for the recovery of survivors, and ability to provide assistance, among other [3, 4]. The SAR coordinator is assigned with the task of selecting the most suitable vessels--a task equally difficult and stressful, performed under pressure of timeand responsibility for one's decision. Their decision largely determines the success or failure of the operation, which can mean life or death for many. The overriding objective is to maximise effectiveness while minimising the risk. An SAR coordinator based at an RCC can deploy available specialised vessels or assign other civil vessels in the vicinity of the distress. The first choice is the specialised vessels at the RCC. However, in certain circumstances, when the time to distress is long (e.g., when the distress position is far away from the shore), assistance of civilian vessels in the vicinity of the site is essential. In Mass Rescue Operations (MRO), carried out for passenger vessels, the number of specialised rescue vessels available can be too small and assistance of civilian vessels indispensable. In selecting suitable vessels, the SAR coordinator uses their best knowledge and experience to compare vessels' potential. In one of the previous papers, the author discusses a mathematical model supporting the selection of suitable vessels. The model, based on the Multi-Criteria Decision Analysis (MCDA), is used to assess vessels under analysis and suggest those which best meet the SAR coordinator's requirements. Various criteria, even ones that are contradictory, expressed in different measurement units, and carrying different weights, can be compared. The result comes as a ranking of alternatives, sorted by the decision-maker's preferences. The method can be part of a Decision Support System (DSS) for Search and Rescue at Sea. In this paper, the author discusses modification of the method with the use of fuzzy logic to build the criteria evaluation methodology. In the standard MCDA, assessments (levels) have fixed boundaries.