August 9, 2010
Pushboat propeller shaft installation exceeds 216,000 running hours
When the 1981-built Rhine river pushboat Veerhaven V was drydocked in the Netherlands earlier this year, the vessel was found to have logged an astonishing total of more than 204,000 running hours on two of its three closed water lubricated sterntube systems, without ever changing its propeller shaft bearings, shafts or shaft sleeves.
According the Technical Department of the owner, ThyssenKrupp Veerhaven B.V., all the Maprom demountable rubber stave bearings (except for the port A bracket bearing which was replaced due to damage in 1992) and their Maprom NCB hard coated tail shaft liners have never been replaced.
During this year's drydocking the measured clearance between bearings and shaft liners, after 28 years of continuous operation, was recorded as a maximum. 2.80 mm.
The Maprom recommended change out clearance for this application, with shaft liner dimensions of 240 mm, is a maximum 4.90 mm. Based on this, the Technical Department of ThyssenKrupp Veerhaven, decided not to renovate the propeller shaft installation - thus extending the running hours to a new record every day. At publication time, the total had reached 216,000 hours.
No shaft withdrawal:
All Veerhaven river push boats comply with Dutch Scheepvaart inspectie rules which do not require shafts to be withdrawn for class inspection every 5 years. As the over shaft clearance of the Veerhaven V is still within acceptable limits it was decided not to pull the shaft or to replace the perfect operating bearings and shaft liners.
In fact the shafts have only been pulled once in its 28 years of existence in order to change from conventional installed stuffing boxes to Maprom GS shaft seal.
During this year's drydocking, the vessel's engines have been overhauled, the propellers balanced and all three nozzles replaced by new ones without removing the propeller shafts.
If well maintained, Maprom systems often operate much longer and or give fewer problems than other systems available on the market. For example, ships sailing with oil or grease lubricated propeller shaft systems need to be docked when aft seals malfunction.
ThyssenKrupp Veerhaven B.V. is a long term customer for Maprom Engineering‚Aeos water lubricated sterntube systems. On all of the Veerhaven operated River push boats, they exclusively operate with Maprom designed / supplied closed water lubricated propeller shaft installations.
The Veerhaven V is part of a fleet supplying raw materials from Rotterdam to Thyssen operations in Germany, providing a "just in time" coal and ore transportation system for the German steel industry in Nordrhein-Westfalen.
ThyssenKrupp Veerhaven's fleet consists of seven push boats -- all having 3 x 1,800 BHP power installations and sailing at a speed of 12 km per hour either with 4 or 6 barges -- one harbor push boat and around 70 pushed barges and two inspection boats.