Marine Stern Tube Oils & EALs — Oil-to-Sea Interfaces

Key Specifications

Technical Detail

The VGP oil-to-sea requirement

The US EPA Vessel General Permit requires that lubricants used at oil-to-sea interfaces be Environmentally Acceptable Lubricants unless technically infeasible. Stern tubes, CPP hubs, thrusters, rudder bearings and wire ropes all fall under this rule for vessels operating in US waters.

EAL chemistry

EALs are biodegradable, minimally toxic and non-bioaccumulative — typically saturated synthetic esters, and in some cases polyalkylene glycols (PAGs). They deliver bearing protection comparable to mineral oils while meeting the environmental criteria; ester and PAG types are generally not intermixable.

Seal compatibility and water tolerance

Converting a stern tube to EAL requires confirming seal-elastomer compatibility and managing the oil's water tolerance, since a small amount of seawater ingress is common. Bearing temperature and oil condition are monitored closely after a conversion.

Ports Where We Supply Marine Stern Tube Oil

Seven Ocean procures and delivers Marine Stern Tube Oil alongside bunker fuel at every major bunkering hub worldwide and across all 25 Indian ports — matched to your engine maker's approvals. Select a port for its full bunkering guide.

International Hubs

Indian Ports

Frequently Asked Questions

What is an EAL and when do I need one?

An Environmentally Acceptable Lubricant is a biodegradable, low-toxicity oil required at oil-to-sea interfaces under the US EPA VGP. If your vessel trades to US waters, stern tube, CPP, thruster and rudder lubricants generally need to be EALs.

Can I mix ester and PAG EALs?

Generally no — ester and PAG chemistries are usually not miscible, and switching between them requires a proper flush. We'll match the EAL type to your existing system.

Do you supply both mineral stern tube oil and EALs?

Yes. We supply conventional mineral stern tube oils and biodegradable EALs, and can advise on VGP compliance for your trading pattern.