Telescopic Tender Crane Overhaul & Dyneema Renewal — Motor Yacht

The captain of a motor yacht berthed at Southport booked us to overhaul the telescopic MARAX crane that launches the tender from her transom garage. First job was making it safe: the crane breaker was locked out and tagged at the switchboard, hydraulic hoses were capped and labelled, and the deck and garage were masked up with film and blankets before a tool came out. Inspection confirmed why the crane was due — the dyneema lifting line was chafed and flat-spotted along its length, the threads securing the arm end plate had stripped, and a tired limit switch needed replacing.

With the vessel alongside and no shipyard crane available, removal came down to rigging. We built a lifting arrangement inside the garage from chain lever hoists, round slings and timber cradles on a scissor lift, secured back to the vessel and dock, and walked the crane beam out over the swim platform onto trestles. The internal extension arm followed, opening up the sheaves so the old line could be cut out and measured — 6.7 metres with spliced eyes both ends — for an exact replacement. The damaged threads were tapped and repaired with new stainless helicoil inserts, two gaskets were custom-made, and new bolts, seal washers and hydraulic hoses went in on reassembly.

Reassembly reversed the lift: extension arm back into the beam, new dyneema rove through the sheaves, hydraulics reconnected to their labelled circuits and the new limit switch fitted and adjusted. Before handing the crane back we proof-tested it with a water bag, then watched it take the full weight of the tender within its 525 kg rated load — smooth through the whole luff and extension range. Three days alongside, no haul-out, and a tender crane the crew could trust again before the vessel's next passage.

Gallery

From the project

Crane breaker locked out and tagged before work began Working out the clearances — garage and crane dimensions sketched on site MARAX telescopic boom opened up for inspection Round slings and bow shackle rigged on the crane cassette lifting point Chain lever hoists taking the beam weight inside the tender garage Crane beam walked out on slings and trestles at the berth — no shipyard crane Chafed lifting line found where it exits the boom-head sheave Old dyneema lifting line measured at 6.7 m for an exact spliced replacement Worn line and swivel snap shackle at the boom-head plate — the failure point Twin dyneema falls over the internal sheave inside the telescopic arm Rope terminations sketched out before the new line was ordered Stripped threads found on the extension-arm end plate New stainless helicoil insert winding into the repaired thread New limit switch alongside the tired unit it replaced New hydraulic hoses made up with colour-coded circuit markers Crane arm underside repainted with rope-retainer clips refitted Crane reinstalled and stowed after passing its water-bag load test