My first one lasted from about 1988 to around 2012. I may have left it in a bit long.
Joe Della Barba Coquina From: CnC-List [mailto:cnc-list-boun...@cnc-list.com] On Behalf Of Michael Brannon via CnC-List Sent: Wednesday, December 18, 2019 7:03 AM To: cnc-list@cnc-list.com Cc: Michael Brannon <ff1...@aol.com> Subject: [EXTERNAL] Re: Stus-List Mechanical shaft seal options I asked about maintenance on the PYI seal and was told to replace the bellows every 5-7 years. I’ve found that it is best to replace the unit as by that time the carbon seal is starting to score and requires replacement also. The bellows is the weak link in the system and since failure of the bellows would be catastrophic I have followed this schedule. I’ve been using the seal since about 1997 and have been very happy with it. Sail Safe, Mike Mike Brannon Virginia Lee 93295 C&C 36 CB Virginia Beach, VA On Dec 12, 2019, at 1:17 PM, Josh Muckley via CnC-List <cnc-list@cnc-list.com<mailto:cnc-list@cnc-list.com>> wrote: Just a week ago a dock neighbor of ours had this exact twisting action completely separate their bellows on a PYI seal. The only indication of a problem from the helm was the fwap, fwap, fwap sound of the vent hose whipping around and hitting the inside of the hull. Evidently the stainless ring a lightly seized to the carbon ring. Seized together the carbon ring rotated with the shaft and twisted up the vent hose until the slack was out and then amputated the vent at its remote barb fitting. Fortunately enough, a remarkably small amount of flooding occurred. When the seal was righted in its orientation the leak stopped almost completely despite the circumferential tear. The owner knew that the seal needed replaced and in fact was about to depart for the boat yard just a few hundred yards away so that they could have the seal replaced during the winter. His other shaft seal looked just about as bad too! On the PYI seals and others with a bellows design, the service life is typically 3 to 5 years before recommended replacement. The bellows has to be flexible so a thinner material is used. Of course the constant stress of compressing the bellows is an additional factor degrading the rubber. In the case of PYI this $2 piece of hose costs ~$100. In the case of the Lasdrop Gen 2 the $2 hose is ridged and thick to resist the compression of the SS spring in the seal pack. The service interval is 8 to 10 years. If I was to go back to a packing style seal what would be involved? Josh Muckley S/V Sea Hawk 1989 C&C 37+ Solomons, MD On Thu, Dec 12, 2019, 12:17 PM Len Mitchell via CnC-List <cnc-list@cnc-list.com<mailto:cnc-list@cnc-list.com>> wrote: Josh, Shawn is correct. The 6 inch or so piece of hose on the original packing gland. I would bet a high number of boats still have it in service. Mine was 20 years old when I replaced it and the outer rubber layer had cracks in it. There isn’t a lot of water pressure on it but it gets a little twisting force. Any original rubber hose should be gone by now. Len Sent from my iPad _______________________________________________ Thanks everyone for supporting this list with your contributions. Each and every one is greatly appreciated. If you want to support the list - use PayPal to send contribution -- https://www.paypal.me/stumurray _______________________________________________ Thanks everyone for supporting this list with your contributions. Each and every one is greatly appreciated. If you want to support the list - use PayPal to send contribution -- https://www.paypal.me/stumurray
_______________________________________________ Thanks everyone for supporting this list with your contributions. Each and every one is greatly appreciated. If you want to support the list - use PayPal to send contribution -- https://www.paypal.me/stumurray
