# Estimating the Human Error Probability during Lifeboat Drills
## 3 Results  
The experts agreed with the tasks performed during the lifeboat drill identified in [32] (Table 1). The tasks were arranged into five groups: before lowering the lifeboat, prior lifeboat crew boarding, launching with crew onboard, recovery of the lifeboat, and post recovery (T1-T5), representing the phases of the lifeboat drill. The identified tasks are used to assist in the estimation of the HEP, which is needed to quantify constants \(a\) and \(b\) (Equation (2)). Figure 1: The sequence of the SLIM and BN-SLIM that were applied in this study. Although the IMO issued revised guidelines for developing operation and maintenance manuals for lifeboat systems where procedures for finalising lifeboat drill tasks together with instructions for inspection and maintenance are given [33], accidents during lifeboat drills still occur. After identifying the tasks involved, the experts defined PSFs. Each PSF was assigned a weight according to its significance for the safe performance of the lifeboat drill. Each expert weighted all PSFs, and then the average values were taken and normalised (Table 2). The highest weights were given to PSF 2, PSF 1, and PSF 3 (Table 2). The authors identified the PSFs that are recognised as the most common causes of lifeboat-related \begin{table}
\begin{tabular}{c c c} \hline
**Task No** & **Task Description** \\ \hline T1 & \multicolumn{2}{c}{Before lowering the lifeboat.} \\ \hline T1.1 & Checking that the Fall-Preventer Devices (FPDs) are correctly fitted to prevent the release hooks from opening (if fitted). \\ T1.2 & Disconnecting the battery cable and checking the engine readiness. \\ T1.3 & Ensuring that sea securing is removed, including harbour pins. \\ \hline T2 & Prior lifeboat crew boarding. \\ \hline T2.1 & Lowering the empty lifeboat to one metre above the sea level (considering weather and sea conditions). \\ T2.2 & Securing the brake with a safety pin and fore and aft painter on ship bits. \\ T2.3 & Checking communication devices. \\ \hline T3 & Launching with crew onboard. \\ \hline T3.1 & The minimum lifeboat crew boarding the lifeboat (wearing Personal Floatation Devices (PFDs) and adequate Personal Protective Equipment (PPE)). \\ T3.2 & Testing engine and steering, confirming the remote control wire is clear. \\ T3.3 & Confirming lifeboat crew readiness and ensuring the rest of the crew is clear from the danger area. \\ T3.4 & Resuming launching the lifeboat into the water. \\ T3.5 & Activating the hydrostatic release, disengaging the hook, and removing the painters. \\ \hline T4 & Recovery of the lifeboat. \\ \hline T4.1 & Aligning the lifeboat with forward and aft davit hooks, retrieving the painter, and engaging the hooks. \\ T4.2 & Confirming crew readiness for recovery. \\ T4.3 & The lifeboat recovery is stopped about one metre above water, the hook FPDs (safety pins or strops/slings) are secured, and the lifeboat engine is stopped. \\ T4.4 & Confirming the release lever is properly rested and hooks locked. \\ T4.5 & Resuming recovery to the embarkation deck level, testing the manual operation of the limit switches during recovery, and disembarking the lifeboat crew. \\ \hline T5 & Post recovery. \\ \hline T5.1 & Recovering the lifeboat to the securing position. \\ T5.2 & Ensuring the lifeboat is secure for the sea. \\ T5.3 & Connecting the battery cable and closing all lifeboat openings. \\ \hline \end{tabular}
\end{table} 
Table 1: Tasks identified during conducting lifeboat drill. \begin{table}
\begin{tabular}{c c c c} \hline
**PSF No** & **PSF** & **Assigned Weight** & **Normalised** \\  & & **(Average)** & **Weight** \\ \hline PSF 1 & Crew Competence & 85.6 & 0.237 \\ PSF 2 & Design and condition of equipment & 89.4 & 0.247 \\ PSF 3 & Leadership and supervision & 80.6 & 0.223 \\ PSF 4 & Written procedures & 52.5 & 0.145 \\ PSF 5 & Shipboard safety culture & 53.8 & 0.149 \\ \hline \end{tabular}
\end{table} 
Table 2: Assigned PSF weights. accidents, according to [7; 34].