Stabiliser & Bow Thruster Overhaul, Motor Yacht Hardstand Refit
A snapped swim platform strut brought us aboard in the water; the haul-out that followed became a full overhaul of both stabiliser fin shafts, the bow thruster gearbox and the platform lifting gear. Sleeve bearings, seals and spacer plates renewed with custom tooling, saltwater-contaminated thruster rebuilt, redesigned billet clevis arms fitted, all signed off underway on sea trial.
The first call was an emergency, not a refit. The hydraulic swim platform of a motor yacht berthed at Coomera was sitting down at the starboard corner, and the captain needed to know whether she could keep operating. We re-torqued and bled the hydraulics and proved the circuit held stable pressure, which cleared the power pack and pointed the fault at the mechanism itself: the starboard lifting strut, a bottle-screw arrangement flagged as a weak point since the vessel was built, had snapped at the thread. We fabricated a replacement support in marine-grade 316 stainless, refitted it in the water, checked the platform dead level with a spirit line and handed it back operational, with the permanent redesign booked for the next haul-out.
That haul-out grew into a four-week hardstand. The headline job was the pair of stabiliser fin shafts, which had been letting salt water past their seals. Both fins came off with extraction tooling we machined for the purpose, one tool cut from an impact socket to release the locking shafts. The composite sleeve bearings behaved like ceramic, too hard to collapse, so each was chiselled out by hand and the housings cleaned back to bright metal. New spacer plates were laser-cut, and the sealing assemblies went back with lip seals, circlips and a marine sealant approved directly by the stabiliser manufacturer for saltwater service. Fitting the new bearings meant building a hydraulic pressing rig on threaded rods, heating the housings and chilling the bearings to win enough clearance, with no margin for a cracked bearing at any point.
The bow thruster told a similar story: gearbox oil drained thick, black and salty, so the unit was stripped to the last bolt, its tapered bearings, seals, gaskets and fasteners all renewed, and the box flushed with clean oil. The swim platform got its permanent fix at the same time. A test on the original clevis arm design showed deformation and cracking, so rather than copy a flawed part we redesigned the arms in solid billet stainless with reinforced welds. With fins refitted and zeroed, thruster propellers back on and the platform rebuilt, we ran the sea trial ourselves: stabilisers driven hard through S-bend manoeuvres, pressures steady at the power pack, no leaks port or starboard, and a platform that finally sat strong and level.
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