# Estimating the Human Error Probability during Lifeboat Drills
## 4 Discussion  
By utilising the SLIM and expert opinions, the highest HEP was estimated for the lifeboat recovery phase of the lifeboat drill. An external validation of the findings was conducted by using real-world data. The Oil Companies International Marine Forum (OCIMF) data showed that almost half of the lifeboat drill accidents occurred while recov \begin{table}
\begin{tabular}{c c c c c c} \hline
**PSF1–PSF5** & **T4.1 HEP** & **T4.2 HEP** & **T3.3 HEP** & **T4.4 HEP** & **T4.5 HEP** & **T4 HEP** \\ \hline R100 probability = 0\% & 10\% & 10\% & 14.2\% & 16.5\% & 14.2\% & 13.5\% \\ R100 probability = 25\% & 7.2\% & 7.2\% & 10.3\% & 12.1\% & 10.3\% & 9.8\% \\ R100 probability = 50\% & 5.1\% & 5.1\% & 7.3\% & 8.6\% & 7.3\% & 7.0\% \\ R100 probability = 75\% & 3.0\% & 3.0\% & 4.3\% & 5.1\% & 4.3\% & 4.1\% \\ R100 probability = 100\% & 0.0\% & 0.0\% & 0.0\% & 0.0\% & 0.0\% & 0.0\% \\ \hline \end{tabular}
\end{table} 
Table 12: Changes in HEP for tasks included in T4—recovery of the lifeboat for changes in PSF ratings. ering the lifeboats [38]. In addition, the same survey results confirmed that equipment failures and design shortcomings were responsible for approximately two-thirds of all reported lifeboat accidents [38]. Tasks T4.1--Aligning the lifeboat with forward and aft davit hooks, retrieving the painter, and engaging the hooks and T4.5--Resuming recovery at the embarkation deck level, testing the manual operation of the limit switches during recovery, and disembarking the lifeboat crew, were identified as the ones with the highest HEP. To reduce the probability of human error during the performance of these tasks, it is important to have well-trained and educated crew members onboard a ship, familiar with the lifeboat davit system and lifeboat equipment, especially with the lifeboat hook release system. Therefore, familiarisation with lifeboats and the associated equipment should be thorough and performed by the officer in charge of the lifeboat. Lifeboat familiarisation checklists should be developed and used to ensure that all equipment, procedures, and actions are covered. Besides this, regular performance of lifeboat drills and training are prerequisites for well-trained and competent crew members. In addition, present weather conditions and the weather forecast should be included in the risk assessment carried out before drill performance, ensuring that environmental factors are favourable. Furthermore, as identified by the experts and confirmed by the lifeboat accident investigation reports, the adequate design and good condition of equipment are important elements of safe and well-performed lifeboat drills, emphasising lifeboat falls (wires) and lifeboat hooks. A lifeboat equipment inspection checklist should be developed (if not already in use) and strictly followed to ensure the equipment is operational and safe for use. Besides that, special attention should be given to regular maintenance, such as lubricating falls and all other moving parts and ensuring that the hooks, together with the on-load release system and limit switches, are fully operational. Inspections should be performed by crew members trained in lifeboat maintenance to ensure the operability of the equipment and improve safety onboard. Fall-Preventer Devices (FPDs) are recommended to be used during lifeboat drills when the lifeboat is not waterborne and during lifeboat recovery when waterborne. When properly used, FPDs could prevent the lifeboat from falling if the hooks open. Therefore, the risk of accidents could be significantly reduced. The crew members must be familiar with the usage of FPDs, which must be in good condition (without any damage). The HEP for Task T4.2--Confirming crew readiness for recovery was identified as the third highest during the lifeboat drill. Although this task does not directly affect accident occurrence, if the lifeboat crew is not seated with seat belts fastened, the consequences of the accidents could be more significant.