RWS switches to oil-lubricated stern seal

02 May 2011
Kennemer, now able to operate reliably in the Frisian Islands where sand and debris played havoc with its old open water lubricated stern tube

Kennemer, now able to operate reliably in the Frisian Islands where sand and debris played havoc with its old open water lubricated stern tube

Dutch public water authority Rijkswaterstaat (RWS) has recently converted its multifunctional ship Kennemer from an open water lubricated to a closed oil-lubricated stern tube system supplied by IHC Lagersmit.

According RWS, Kennemer formerly sailed in relatively shallow waters, until RWS decided to deploy the ship in the West Frisian Islands area. Even though the original system functioned well in deep waters, RWS says that it failed in the new unpredictable area, because of debris and sand entering the stern tube, disastrous for an open water lubricated system.

IHC Lagersmit says its Supreme  lip seals and bearings were chosen by RWS, as the technology is diametrically opposed to the water lubricated system. The closed oil-lubricated system is designed to ensure oil stays inside and water keeps out of the stern tube. To protect the system against sand and debris the aft seal is equipped with multiple lip seals and an extra dirt barrier. The ships 80mm shaft was retrofitted with a new 110mm IHC Lagersmit seal, type LDA (aft) and LDF (forward) which includes a forward bearing bush, and features three NBR lip seals, running on chrome steel liners, and a dirt barrier.

“We find that problems with sand and debris are the number one reason to switch from open water to closed oil-lubricated systems”, Jan Boomsma (application engineer with IHC Lagersmit) explains.

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