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The MV Bison was a 142m long 11,7723 GRT Freight Ro-Ro ferry owned by Pandoro Ltd with a capacity for 120 units and managed by P&O European Transport Services. In 1997 the vessel suffered damage to the propeller and three sections of the line shafting. Ship repairer Wright & Beyer of Birkenhead undertook the repair.Due to the known problems of conventional coupling bolts it was decided by Mr. Steve Seal of POETS to take advantage of the dry dock time and replace the existing bolting solution for the propulsion shaft. Conventional bolts have always been prone to seizure, requiring forceful removal. This usually damages the bolts so severely that their replacement and bolt hole re-machining is essential. To ensure the quickest and most cost effective repair turnaround, the MV Bison was dry-docked and the damaged shafting removed through an aperture cut in her side.
The hydraulically actuated PILGRIM Radial Fit Bolt provide the most economic solution. Using the Radial Fit Bolts means bolt removal and re-installation is now predictable helping the maintenance procedures remove uncertainty allowing for accurate planning and budget scheduling. The principle of the bolt is of a taper shank bolt drawn into a matching taper sleeve with parallel outer diameter which expands fractionally to produce a perfect interference condition in to the bolt hole. This condition, which “conventional” fitted bolts do not achieve, eliminates movement between mating components.
“The speed and dependability with which PILGRIM bolts can be removed and reused indefinitely without damage to either the bolts or bolt holes, was a major consideration for us. In the fitting of the PILGRIM bolts we have made another investment in the future of the MV Bison Ro-Ro to achieve improved serviceability and minimise any down-time resulting from further shaft removal”
Mr. Steve Seal – POETS Ship Management Superintendent
