SKF Marine: Leading the Way in Sterntube Seals for Modern Shipping
Why sterntube seals matter
On any ship, the sterntube is a critical part of the propulsion line: it houses the propeller shaft where it exits the hull, and must prevent seawater ingress while keeping the lubricating oil contained. Failure here can lead to water ingress, oil leakage, shaft bearing damage — and in worst cases, major downtime or environmental pollution.
Traditionally many vessels have used standard oil-lubricated sterntube systems. However, with stricter environmental regulations (such as the Vessel General Permit 2013 (VGP) in US waters, or the requirements of the Polar Code for ships in polar and other sensitive zones), shipowners increasingly demand sterntube solutions that minimise risk of oil-to-sea interfaces and environmental impacts.
That’s where SKF Marine’s sterntube seal range shines — offering reliable, high-performance sealing solutions that help vessel operators meet both operational and regulatory demands.
SKF Marine’s Sterntube Seal Solutions
As part of the marine division of the SKF Group (originating from the historical Blohm + Voss shipyard), SKF Marine offers a wide portfolio of shaft-line and sterntube solutions: sterntube seals, bearing bushes, complete sterntubes, lubrication & water-lubrication systems, and related services.
Key sterntube seal products include:
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SIMPLEX-COMPACT / SIMPLEX seals — lip-type or face-type seals (or combination), suitable for oil- and water-lubricated propulsion systems, over a wide range of shaft diameters.
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Air-seal solutions, notably Simplex Airspace, which use an air-filled chamber to separate seawater and lubricant — eliminating any oil-to-sea interface and thereby preventing oil leakage and seawater ingress.
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Water-lubricated sterntube systems, e.g. Simplex BlueRun, designed for vessels where water lubrication is preferred or required (e.g. polar ships, protected waters, vessels needing full compliance with oil-discharge regulations). The BlueRun system includes polymer bearing bushes, a water-quality and flushing system, and a tail-shaft monitoring system to track wear and ensure safety.
Environmental Compliance and Long-Term Cost Efficiency
One of the major drivers for modern sterntube seal choice is compliance with environmental regulation. The Simplex Airspace seal is officially certified as a “non-pollution” sterntube seal by all major classification societies — under normal operating conditions, the oil and seawater are fully separated, preventing leaks.
Because the air-seal system eliminates oil-to-sea interfaces, the vessel can often continue using standard mineral oil for lubrication, avoiding the need for expensive Environmentally Acceptable Lubricants (EALs), which are mandatory under VGP 2013 for conventional oil-to-sea interfaces.
Beyond environmental benefits, sterntube systems like Airspace or water-lubricated BlueRun significantly reduce total cost of ownership. By preventing leaks and water ingress, they protect bearings and extend shaft line life — avoiding costly dry-dockings, repairs and unplanned maintenance.
Practical Benefits: Safety, Reliability & Vessel Uptime
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Pollution-free operation — Airspace seals eliminate oil discharge; water-lubricated systems avoid oil entirely. This is critical for vessels operating in sensitive or regulated zones.
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Robust, tested solutions — BlueRun polymer bearing bushes were tested under real conditions for thousands of hours to ensure durability in harsh marine environments.
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Reduced maintenance & spacing needs — Some seal solutions (e.g. from Simplex) feature split designs that allow seal servicing or replacement without removing the propeller shaft — a big advantage during overhauls or retrofits.
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Flexibility for shipyards and retrofits — SKF Marine sterntube and seal solutions can be tailored for a wide range of vessel types, shaft diameters, hull forms — even in challenging scenarios (e.g. vessels with flat hulls or special draft requirements).
Conclusion: Why SKF Marine Sterntube Seals Stand Out
For shipowners, shipyards or marine contractors looking for reliable, regulatory-compliant sterntube solutions, SKF Marine’s seal range represents a mature, proven option that balances operational safety, environmental responsibility, and long-term economy.
Whether opting for the classic oil-lubricated Simplex seals, switching to the environmentally friendly Airspace air-seal system, or choosing water-lubricated BlueRun for total oil-free operation — SKF Marine provides a full spectrum of solutions to meet modern shipping demands.
Given PartYard’s expertise in global marine supply and spare parts — including genuine components and control equipment — positioning SKF Marine seals within your offering could represent a strong value proposition for clients seeking reliability, sustainability and regulatory compliance.
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Contact us today: +351 265 544 370 or go to Contacts Page
Email: sales@partyard.eu
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