Repairing a 55-year-old gearbox is a testament to the sustainability and long-life product quality of the equipment. It demonstrates that the gearbox was built to last and was made with quality materials and craftsmanship.
The reduction gear from Volda was delivered to the ferry MF Florøy in 1968 as part of a NORMO delivery. In the documentation from the testrun of plant no. 16 and 17, we found a handwritten note saying "Good gear. Nice running. 15/2-68". And now, 55 years later, we got confirmed that it was a “Good gear”. In the records for the installation, we read that only minor service tasks have been carried out since the delivery in 1968.
February 2022, Kennet Håskjold was inspecting the installation at MF Levanger (ex MF Florøy). The gearbox was still in working condition but seemed worn with indications of loose gearwheels.
The shipping company considered whether to repair the old unit, and in February a year later it was decided to dismantle the gear. It turned out that the theory was correct, the gear was generally worn after 55 years, and the gear oil cooler had at one-point leaked salt water into the gearbox, which had caused damage to the white metal bearings.
Brunvoll owns all necessary drawings for all products that have been delivered over the years and has both the expertise, machines and tools to produce most of the larger parts directly from the factory in Volda.
As mentioned, the gearwheel which should be firmly shrinked onto the shaft was loose. Then Øystein Fet, Principal Engineer Mechanical Design, designed new shaft with new tolerances. The shaft was produced at the factory in Volda, and the original gearwheel was shrinked onto the new shaft.
All white metal bearings in the gearbox were replaced due to wear and saltwater intrusion. Brunvoll has its own white metal production and makes all white metal products from the factory in Volda. New and updated models of the bearings were made with new lubrication grooves and bearing clearances.
The original pump from 1968 was checked and found in good condition for further operation. The original clutch hub looked worn but after cleaning from rust it was restored for further operation.
The new and overhauled parts were transported back to MF Levanger and Kennet Håskjold and Christian Myklebust could complete the job of assembling and reinstalling the gear in the ferry. The original Normo Semidiesel engines had been replaced by MAN engines in 1995, but both gearboxes are still running 55 years after delivery.
MF Levanger is owned by Torghatten Midt AS and operates as emergency ferry on the Levanger - Hokstad connection in Norway, and during summer as supplementary ferry on the same connection in weekends.
The propulsion system on the ferry consists of two reduction gears, plant no.: 16 and 17, delivered from Volda Mekanisk Verksted in 1968. Plant 17 was repaired after a breakdown in 2014. Now it was plant 16 that showed signs of wear and tear. The owner had to think twice whether it would be worthwhile to repair the gear, but in the end they chose to carry out the overhaul and necessary repairs. The work on plant 16 was extensive, with both machining of new parts but also a lot of reuses of original parts from 1968.
The Normo diesel engines that were installed together with the gearbox in 1968 had been replaced with MAN diesel engines in 1995, but both gearboxes are still in operation 55 years after installation.
The Normo Diesel engine was a collaborative project between the Norweigan companies Bergen, Brunvoll, Hjelset and Volda, where BMV (Bergen Mekaniske Verksteder) was responsible for the engine delivery itself, while the others supplied parts for the engine. Both Bergen, Brunvoll, Hjelset and Volda had their respective diesel engines until approx. 1965, and after that time they agreed to deliver a common engine in the Normo Semidiesel. The Normo Group was established in 1958 with the purpose to promote Norwegian engine production, and the specific agreement for the production of the common Normo Diesel ended April 30th, 1980.