Gear Oil Maintenance, Thruster | Harbour Tug

System — Thruster

Vessel: Harbour tug “VB PORNIC”
Thruster: AQUAMASTER US 1401 AZIMUTH Starboard Thruster
Gear oil: EPONA Z 100 (marine mineral gear oil)
Viscosity: 100.7 cSt @ 40 °C
Oil volume: 850 litres

Challenge

Entry of seawater into the gear oil of the thruster of the tug (starboard side). The mineral oil-based gear oil was contaminated with water (0.39%) and sodium (22 ppm). As the next inspection in the dry dock was not scheduled for another 6 months, our customer was urgently looking for a solution to be able to operate the tug reliably until then.

Solution: CJC® Thruster Filter

A CJC® Thruster filter consisting of Desorber D5 and oil care system 15/25 was installed. The installation of the CJC® Thruster Filter in the offline circuit ensures continuous dewatering, fine filtration and maintenance of the gear oil (24/7/365). Water — free, emulsified and dissolved — as well as wear particles and oil degradation products (varnish, acids) are removed from the gear oil very efficiently.

Water separation capacity: > 150 ml/h
Dirt holding capacity: approx. 1.1 kg
Filtration degree:3 μm absolute, 1 μm nominal
Filter material: 100% natural fibres (cellulose)

BEFORE — without gear oil maintenance

Result of gear oil maintenance

Weekly oil samples were taken to follow the oil condition and trend. After a week, the CJC® Thruster Filter had removed the water from the gear oil — the water content in the oil dropped from 3,904 to 163 ppm. According to Noria Corporation, this corresponds to a lifetime extension factor of 5-6 for the oil and equipment. The recommended water content of the gear oil amount < 300 ppm. Moreover, the CJC® Thruster Filter removed solid particles from the gear oil — wear debris such as iron (FE) and copper (CU) were lowered from 29 and 4 ppm down to 17 and 1 ppm; the sodium/salt content (NA) decreased from 22 to 13 ppm. The content of these impurities should not exceed 25 ppm as recommended.

Oil samples

Savings and Benefits

The installation of the CJC® Thruster Filter results in the following advantages for our customer:

• cost-intensive emergency inspection in dry dock avoided
• oil filling service life and thruster components extended by 5 to 6 times
• oil change avoided and 850 litres of gear oil saved
• permanently clean and dry gear oil ensured – free of water, wear particles, and salt crystals/sodium

By avoiding the oil change and drastically extending the service life of the oil filling in the future, the CO₂ footprint of the tug improves – a valuable contribution to BOLUDA’s strategic goal of becoming a CO₂ neutral company.

Customer Comment

“The CJC® Thruster Filter allows us to keep the tug in operation until the scheduled dry dock inspection in 6 months. The results of the oil analyses are clear and clearly demonstrate the effectiveness of the CJC® Thruster Filter.”

Regional Technical Manager, Mr. Olivier GLOAGUEN