|
CONCLUSIONS
3.1 The crew paid out a reasonable amount of chain, for a standard yacht, in the weather conditions at the time of anchoring. This was in accordance with their training.
3.2 Although the type of anchor fitted to the Mirabella V is different to that fitted on most merchant vessels, the size and purpose of the chain is very similar. The merchant philosophy, with regard to a greater amount of chain to be paid out (scope), may have been more appropriate, especially when the weather deteriorated.
3.3 The tendency of Mirabella V to swing at anchor, coupled with a short scope of cable deployed, caused a lateral load on the anchor shank.
3.4 The anchor was pulled out from its holding position by a large transverse pull on the anchor shank, possibly cyclical as the yacht swung about her anchor.
3.5 The anchoring equipment provided to Mirabella V is well in excess of the of the DNV minimum rule requirements.
3.6 There are large differences between the requirements of the various Classification Societies. This is in contradiction to the assumption by the industry and the Large Yacht Code that Class represents a common standard.
3.7 The frontal area of the rig is more than the frontal area of the hull and therefore should have been factored into the calculations for the size of the anchoring equipment fitted. The Classification Society Rules, relating to the anchoring equipment, which are based on empirical formulas derived from standard motor vessel designs, do not adequately cope with the design of this yacht.
3.8 The designers used the most onerous Classification Rules available to them (LR), which required much larger equipment than the DNV Rules, in accordance with which the yacht was being built. However it is argued that because of the Mirabella V novel design, additional safety factors for rig windage should have been applied or the equipment should have been assessed by direct calculation, perhaps supplemented by wind tunnel model testing.
3.9 The yacht did not ground because of a failure in the hydraulic lifting system for the keel.
3.10 The selection of the anchoring position was not unsafe in the light and variable wind conditions prevailing when the yacht anchored. This anchorage would be the preferred anchorage over Villefranche, had the wind turned to the South West.
3.11 The Master did not take into account all the information available to him preceding the incident, including weather forecasts, so that the decision to weigh anchor and move to Villefranche was taken too late.
3.12 Once the decision to remain anchored off a lee shore had been made, prudent measures should have been taken to improve the anchoring arrangements in the increased weather conditions.
3.12.1 At the time of the incident, the Master was in the bridge and fully aware of the conditions. The Master became immediately aware when the anchor began to drag by looking out the bridge windows and observing a sudden change in heading (the bow falling away to starboard).
3.13 Although the engines were swiftly started by the Engineers, the time lag proved too long. The vessel was not in a suitable state of readiness, given the high level of risk created by the yacht’s position and the prevailing weather conditions.
RECOMMENDATIONS
4.1 The MCA and other Administrations issuing qualifications for yacht masters on large yachts should reassess their requirements for training in anchoring techniques to reflect the existence of very large yachts.
4.2 The crew of this yacht should develop techniques for reducing the amount of swing at anchor. The owners should provide the necessary technical back up and equipment to enable them to do so.
4.3 The owners should work together with DNV to reassess the capabilities of the anchoring equipment fitted to this yacht.
4.4 All Classification Societies, involved in classing large yachts, should re-evaluate their Rules pertaining to yacht anchoring equipment and work together through IACS to develop a common standard, relevant to these types of vessel.
4.5 Owners should provide more guidance within their ISM system for the allowable parameters for anchoring and remaining at anchor, on a lee shore.
4.6 Owners should reconfigure the engine platform management system to provide a safe option for leaving the propulsion system in an immediate state of readiness at anchor. In an emergency, the propulsion system starting sequence should be easy to initiate, by the Anchor Watch Keeper, from his watch keeping position, without the assistance of an Engineer. The vessel’s procedures should specify the various states of engine readiness options available and the characteristics of each.
|
