Double Gearbox Replacement

Initial Findings

We carried out a pre-purchase mechanical inspection and during the inspection we noticed various issues that needed addressing. We took oil samples from the engines and gearboxes, and found the wrong grade of oil in both gearboxes. The engine oil samples tested okay but the gearbox oils samples were metallic with chunks of metal and we were able to remove the metal particles using a magent. Along with a few other faults found during the inspection/service on both engines we decided with the owner it would be good to get the boat out of the water undercover at Tamaki Marine Park to allow us to work on it without being affected by weather conditions. We replaced both gearboxes, water pumps, engine mountings, and flushed the starboard cooling system. 

 Workshop Trailer-on-Site
Floor Protection Mobile Workshop

Shafts and Gearboxes out 

We had to remove the rudders to allow room for the shafts to come out and due to a vibration while underway on sea trial, we replaced both cutless bearings. We could also see evidence of whipping on the shaft where a gouge had appeared. Due to this we decided a half bearing at the top of the shaft tube would be appropriate. While both gearboxes out we checked both dampers and both were worn and in need of replacing. 

 Shaft Out
Corroded Pump Impeller Bits

Water Pump and Mountings

This vessel had motored from Singapore to Auckland without having an impeller change due to poor access and lack of maintenance. After 800 hours on the same impeller the pumps were leaking from the void and bits of the impeller had shredded and spread into the heat exchanger. Water from the pumps was rusting out the mountings so they were also replaced. We backflushed the cooling system on the starboard side to get rid of all the silt using a hose and compressed air.

 Floor Protection
Rusted MountingImg 2537

Sea Trial

After the work had been carried out we had two engineers on board to check over the work while the boat returned to a temporary berth at Bayswater Marina. Once we were happy that all work was complete and up to our standard, we removed all our protective flute board from the floor and did our final checks and cleanup before the vessel went down to the Coromandel.

 Boat Being-Lifted-in-Water
Boat In-WaterSea Trial