Hi all....did the anchors really fail?????????????????????????...I think not!
One of the issues with hydraulic tension/mooring winches is
1) the vessel may have has two anchors out
2) these would have been locked in mechanical stoppers on deck & with the windlass mechanical brake band tensioned
When the inclement weather appears...a series of events occur
3) start the hydraulic system
5) release the mechanical windlass brakes
6) attempt to haul in the anchors
This is where the scenario begins..........
7) the windage against the vessel hull is greater than the hauling capacity of the winches
the manual directional control valve is returned to neutral...all ports blocked center
9) the continued force of the windage against the vessel means the vessel moves, but the anchors are locked & hence the hydraulic winch internal rotating vane elements [400 Bar synthetic] are distroyed
The first 100,000 tonner....1966 Japanese IHI built Sig Silver/Chelsea Bridge/Iron Sirius had IHI Norwinch winches built under licence & had cross line relief valves set to 350 Bar which negated the problem noted at point 9)
20 years later BHP Steel ordered four new 100,000 ton bulk ships for the iron ore trade ....but as a cost cutting measure the windlass cross line relief valves were not installed
So after a few cyclones off Port Hedland....& ships loosing an anchor or so & hence loosing Lloyds classification to sail.
..we had the task of retro fitting the 100 kg blocks of cross line relief valves .....
So did the anchors drag?....I thought the water off Gibraltar was rocky.....surely they would not have placed the vessel with out an emergency engine start up time?......Derek