Summary of The Vessel, Equipment, and Operating Arrangements
Honeybourne III, a scallop dredger built in 1983 and converted for its purpose in 1996, operated using a system of two derricks with a quick-release mechanism. This mechanism, which included seven links of 32mm Grade-8 chain, was intended to facilitate emergency gear jettisoning during scenarios like snagged dredges. However, complexities arose when the chain bent around a static pin, subjecting it to unusual stresses. While the chain had a working load limit (WLL) of 31.5 tons in a straight line, shock loads exceeded normal tensions during operations, leading to high stress points that eventually caused a chain link to fracture.
Findings from the MAIB Investigation
The Marine Accident Investigation Branch (MAIB) conducted a thorough investigation into the failed components, uncovering serious defects and safety concerns. The failure mechanism of the chain was identified in two stages: one shank fractured in a brittle manner while the other yielded ductilely. Significantly, the failed link had hardness levels above recognized limits for marine applications, increasing its risk of sudden failure. Despite adhering to original specifications, the chain showed reduced ductility due to wear and deformation, particularly at points of critical stress.
The investigation also revealed severe wear on the derrick head components, with substantial damage to the static pin and cheek plates. Issues such as a seized rotating collar led to misalignment of loads, further exacerbating wear and impairing the functionality of the assembly.
Inspection and Maintenance Deficiencies
Although components had been replaced in 2022, by 2023, they exhibited wear that was “well beyond acceptable limits.” The inspections conducted by the skipper failed to provide clear criteria for assessing wear, and responsibilities appeared to be informally passed to less knowledgeable crew members. The MAIB noted a history of similar failures within the same fleet, indicating a systemic issue.
Safety Management System Failings
The MAIB identified several flaws in the Safety Management System (SMS). Despite protocols prohibiting crew from working beneath suspended loads, the vessel’s design made compliance impractical. In addition, issues like non-compliant personal protective equipment (PPE) usage suggested deficiencies in safety enforcement.
Regulatory Oversight Issues
The MAIB pointed out that the Maritime and Coastguard Agency’s (MCA) oversight of lifting equipment on fishing vessels lacked thoroughness. Annual surveys were overly reliant on shipboard inspection records, and surveyors were inadequately trained to identify lifting gear defects.
MAIB Report Conclusions
The investigation led to the identification of seven key safety issues, including the dangers of crew working under suspended loads and the failure to recognize risks associated with chain-over-pin arrangements. Other concerns included excessive loading, wear-induced stress concentrations, and ineffective inspections.
Actions Taken Following the Fatality
In response, Macduff Shellfish initiated a series of corrective measures, including replacing outdated configurations, instituting regular inspections, enforcing no crew beneath suspended loads during winch operations, and mandating formal training for personnel. The MCA has also undertaken inspections of similar vessels to address widespread deficiencies identified in safety procedures.
Recommendations Issued by MAIB
In its safety bulletin, the MAIB urged vessel operators to inspect quick-release arrangements and update equipment and operations to safeguard crew members. This emphasis on preventive measures highlights the importance of proactive safety protocols to avert similar incidents in the future.
