Conical Rudder and Rudderstock Repair: On-Site and in Drydock
In-Situ and workshop machining repair
A vessel owner approached Goltens to evaluate the repair of a damaged rudderstock on its vessel in a drydock in Spain. Goltens specialists inspected the rudderstock and prepared a detailed repair procedure consisting of repairing the rudderstock in Rotterdam, machining the rudder in–situ and fabricating a stepped insert bush. The proposed process was reviewed and approved by the customer and Class.
The Rudderstock, with a 1:15 taper, was inspected, cleaned and machined in the workshop. Goltens was able to save the bearing sleeve but the oil grooves and O-ring grooves required restoration. Also, the rudderstock nut was repaired and the SKF-pump ring was overhauled including a newly fabricated piston ring.
To accommodate the smaller rudderstock, the conical bore in the rudder needed to be machined to undersize and a stepped bush inserted. Goltens manufactured the bush within very tight tolerance, and the bush and the rudderstock were blue fitted in the workshop.
Onsite in Spain, Goltens In-Situ Specialists machined the rudder to a diameter of 800mm and a depth of 910mm. Goltens then used liquid nitrogen to freeze the bush and insert it in the rudder. The rudderstock was blue-fitted into the rudder and due to the precision of the machining, only two blue fits were necessary for acceptance by class.
Rudderstock installed on lathe in worshop
Machining of rudderstock
Boring equipment installed
Example: 5Blue fitting of stepped bush
Installation of stepped bush
|Vessel dimensions:||175 x 30|
|Rudderstock sizes:||8m x ø750, 12 Ton|
|Rudder sizes:||10x3m, 15 Ton|
- Workshop machining of 1:15 taper rudderstock and restoration of oil and o-ring grooves
- Fabrication of stepped bush for insert and bluefitting with rudderstock
- In-Situ machining of Rudder (800mm dia x 910mm deep)
- Installation of stepped bush in rudder
- Blue fitting of rudderstock and bush
Goltens continuously monitored the entire assembly process of the rudderstock and the rudder which was completed by hydraulic press-up method. The reassembly of the rudder was successful and the vessel was returned into service 3 days before the delivery date stated in the original repair planning to the complete satisfaction of the owner and class society.
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