# Maximum Safe Parameters of Outbound Loaded Vessels for Wind Turbine Installation
## 2 Offshore Wind Turbines and Vessels for Their Installation--Current Status and Development Trends
An analysis of the characteristics of WTIV vessels in service as of 2021/22 shows that only 12 of them are currently capable of installing turbines above 10 MW [16]. To meet the market needs, shipowners are currently building several new WTIV. For example, [PERSON] is currently building the largest jack-up vessel, called Voltaire [17]. Voltaire has a specially designed positioning system that makes the vessel capable of operating in sea depths of up to 80 m. The lifting capacity of the main crane is over 3000 tons. Voltaire is expected to be completed in 2022 and has already been contracted to install the GE Haliade-X turbine in the Dogger Bank project in 2020. Although only a handful of new WTIVs are being built in 2021, a number of offshore wind industry shipowners have signed contracts to build new vessels. Triumph Subsea Services signed a letter of intent to build two WTIV vessels, designated GustoMSC NG-2000X, with planned entry into service in 2023 [18]. [PERSON] of Norway has published a new design for his jack-up vessel, named ATLAS Class C, for installation of wind turbines of 20 MW or more [16]. With an overall length of 170 m, a width of 60.2 m, and a draft of 6.7 m, the ATLAS vessels, equipped with a 3000-ton crane, will have the capacity to transport at least five complete 20 MW turbine assemblies [19]. Figure 2: Estimated number of WTIV vessels in the world fleet categorized in terms of OWT generated power [6]. Navigational Risks of Maneuvering in Port Waterways of a Loaded Wind Turbine Installation Vessel (WTIV)  
If a vessel passes through a waterway with deck cargo extending beyond the contours of the vessel's sides, there is a possibility of the vessel (deck cargo) striking a hydrotechnical structure or moored vessel even with basic navigation safety condition fulfilled [20,21]:  
\[D_{i}\geq d_{i(1-\alpha)} \tag{1}\]  
where:  
\[  
Safety of navigation can be assessed using navigational risk (maneuvering risk). Navigational risk is equated with the risk of ship accident while maneuvering in a restricted area. Maneuvering risk for all types of waterways (maneuvers performed on them) can be represented as a function [20,21]:  
\[R_{i}=f(A_{i},Q_{i},N_{i},H_{i},M_{i},I_{i},Z_{i}) \tag{7}\]  
where:  
\(R_{i}\) -  
\(A_{  
\[R_{s}\] - Risk of an accident resulting in the death of a person; \[P_{A}\] - Likelihood of an accident in which human life is at risk; \[P_{sp}\] - Probability of a person dying as a result of an accident. As a condition of accepting a fatal accident, the relationship must be met:  
\[R_{s}\leq R_{s\;alc} \tag{12}\]  
where:  
\[R_{s\;alc}\] - Acceptable risk of fatal accident. The acceptable risk of a fatal accident in shipping is assumed to be [22]:  
For a crew member: \(1\times 10^{-4}\) (\(1/\)year);  
For a passenger or a group of crew members: \(1\times 10^{-5}\) (\(1/\)year);  
For a group of passengers: \(1\times 10^{-6}\) (\(1/\)year). It should be noted that the economic impact risk analysis can proceed when the human death risk condition is met. Figure 3 presents the basic flowchart for calculation of the permissible safe length of wind turbine blades. A Method for Determining Maximum Safe Blade Lengths of Wind Turbines Loaded across a Jack-Up Vessel in Port Waterways  
Contingency scenarios (accident types) are specified for maneuvers performed by ships of a given type and size based on hazard analysis and accident statistics in specific bodies of water. The emergency scenarios do not take into account navigational mistakes made by humans, which are classified as gross errors. Instead, they take into account accidental and systematic errors of all types of navigational measurements and assessments and maneuvering inaccuracies committed by a navigator with specific qualifications while maneuvering the vessel [23].