John: I have tried the Drip Less Seals by two companies. La Manya Company in Florida and PYI in California _www.pyi.com_ (http://www.pyi.com) I used them on my sailboat as well as my trawler. The "Last Drop" seal by Lamanya leaked like a sieve while PYI was truly drip less. Plus the Tech support from PYI is Great. The Lamanya ? Company In florida and the Folks AT PYI have a similar design but different components. The surface LamanYa uses is a synthetic plastic to run on the face of the stainless steel rotor while PYI uses a superior Carbide face. I switched to PYI a long time ago. You want the PYI Nitrile rubber bellows which will outlast both out life times. Patching? Not sure what you mean you do not patch Nitrile Rubber it is about bullet proof. Visit the PYI website at _www.PYI.com._ (http://www.PYI.com) They use their products on Military ships as well I am sure your Nordhavn will benefit from the PYI Product. Best Regards Capt Bob Kovach M/Y ALLEZ ! Charleston, S.C.