92 
Appendices 
• The convergence criteria shall be documented for both implicit and explicit simulations. 
There shall be no major damping (material damping, etc.). Friction coefficients shall be se 
lected reasonably. 
• Energy distribution shall be considered in detail by the simulation. Changes of the total 
energy level, in particular, shall be documented. 
Risk analysis and assessment 
The quantitative risk analysis shall combine the results of the occurrence frequency with those 
of the collision analysis. This shall then be assessed on the basis of a risk matrix. 
Please refer to the subsequent risk matrix for the respective risk priorities (Table 1.3). The de 
termined risk priority of each individual scenario shall not exceed level 4 for offshore wind 
turbines, resp. level 3 for ships, the environment and the safety of individuals. 
Catastrophic 
4 
5 
6 
7 
Serious 
3 
4 
5 
6 
Significant 
2 
3 
4 
5 
Insignificant 
1 
2 
3 
4 
Extremely rare 
Rare 
Occasionally* 
Frequent* 
Table 1-1.3: Risk matrix with risk priorities 
Determining the Behaviour of Offshore Stations in the Case of a Collision 
The requirements placed on a “collision friendly”, resp. hull-retaining method of construction 
shall also apply to all other offshore structures, such as offshore stations. However, when ta 
king the above mentioned risk-based approach into account, there are some differences 
when it comes to the assessment of the behaviour of the support structure in the case of a 
collision. Among other things, it may be taken into consideration that the support structure of 
an offshore station may, due to the dimensions and construction methods involved, possibly 
be engineered with a higher strength in order to comply with the stability criteria. Furthermore, 
because of the relatively small number of substations and converter platforms compared to 
the number of offshore wind turbines, and due to the size of the traffic areas actually occupied 
by these structures, one can assume that the probability of a ship specifically colliding with a 
platform is lower. 
In this respect, the expert opinions on the analysis of the behaviour of the support structures 
in the case of a collision must include a comprehensive treatment of a collision of a ship with 
an offshore station, but may also consider modified requirements. In particular, in considera 
tion of the above mentioned criteria and requirements, the extent to which the platform has 
been designed to make it as “collision friendly” as possible must be accordingly demonstra 
ted. In those cases in which the danger to ships, safety or the marine environment has been 
classified “Significant”, specific alternatives shall be additionally assessed and represented in 
order to minimise the hazards to ships, safety and the marine environment. 
* Based on the acceptance criteria with regard to the readiness for approval of offshore wind farms fixed by the 
BMVI working group “Approval-relevant Recommended Guidelines” (not more than one collision cumulated 
within 100 years), it can be assumed that, for the analysis of the behaviour of the wind turbine in the case of a 
collision, the probability of occurrence of a collision classified “Occasional” and “Frequent” is not admissible and 
therefore not significant in practice.