Vessel General Permit (VGP)


Please note that this advice is given in good faith, but we cannot accept any responsibility for the contents of this document, which should be verified by the recipient. 


Advice on the Vessel General Permit (VGP 2013) regarding Sterntube Seals

All vessels sailing in US waters must comply with the latest Vessel General Permit (VGP) regulations. This means that whenever such a vessel next drydocks, all seawater / oil interfaces must be controlled in order to comply with the regulations.

With regard to sterntube seals, there are a number of different ways in which a vessel can comply depending on the existing installation. The optimum choice between these options will depend on a number of factors, such as:

· The number of pipes already fitted to the aft seal
· Whether the tailshaft will be drawn or not
· The period between scheduled drydockings
· The age of the vessel
· The future plans for the vessel
· The volume of sterntube oil including on-board reserve stocks
· The price differential between your mineral oil and the EAL

We are very happy to advise on the different options available irrespective of the make and type of seal providing a price comparison for each potential solution. Simply send a list of your vessels which are due to drydock in the near future together with their IMO numbers to Each vessel must be considered on a case by case basis, but here are some of the potential solutions.


The Airspace Solution. These seals have no seawater / oil interface in normal operation. This means that a vessel fitted with an Airspace seal already complies with the regulations and can continue to trade with traditional seal materials and mineral oils. However, the vessel should carry a copy of the GL / DNV confirmation that there is no oil / water interface, which can be requested by sending an email to with the vessel particulars.


The new SIMPLEX BIO seal solution. This seal can provide a full five year docking period when operating with an EAL without any special operating restrictions. The BIO seal is currently only available on the SC3 seal.


Replacement of the old seal material with Viton Pod seals. Where the aft seal has a flushing system, this is an effective and cheaper solution in order to obtain a full five year docking period, but there are restrictions to the operating parameters which the crew must adhere to. Alternatively, an automatic Oil Dryer Circulating system can be fitted to avoid crew intervention and guarantee oil quality.


Conversion of the SC1 and SC2 seals to SC3

All SC1 and SC2 seals can be converted to SC3 in which case the SIMPLEX BIO seal can be used.


The Certificate of Infeasibility. This is available for installations where it is not possible to achieve the normal docking cycle. Under these circumstances the vessel can continue to operate with its old sealing system using mineral oil. However, it is essential that the certificate of infeasibility is retained on board.


Further information from SKF Marine can be found at

Justin Brooking
Managing Director October 2016