I appreciate the comments from everyone. The 1/4 inch packing I used went into the gland nut with just finger pressure, so I'm assuming it won't be so snug as to overheat the shaft. I tightened the gland nut only by hand. I have an IR thermometer at the ready for Wednesday's launch to monitor heat at the stuffing box. If it runs hot, I guess I'll have to unpack and downsize the stuffing once more. Where my gland nut is, there's a faint bluish discolouration on the shaft which is likely evidence of some past heat or glaze from the packing - no scoring though. I'll be keeping an eye on that as well.
Jason Ainslie, Spirit 1984 C&C 35-3 Bayfield, ON -----Original Message----- From: CnC-List [mailto:cnc-list-boun...@cnc-list.com] On Behalf Of Steve Thomas via CnC-List Sent: May-12-18 3:59 PM To: cnc-list@cnc-list.com Cc: Steve Thomas Subject: Re: Stus-List Stuffing box material One other thing on packing, for those who do a seasonal haul out. Don't freak out if there is a fair amount of water coming in around the packing in the spring, so long as you haven't monkeyed with the stuffing box over the winter. Give it a day or two before you decide to move the packing nut. If it was not leaking in the fall, give the flax some time to absorb some water, and the leak will usually stop. Over tightening is usually what wears it out, so long as there are no major mechanical problems that lead to excessive vibration and so forth. Steve Thomas C&C36 C&C27 MKIII PS: 3/16 shaft packing will work for the piston rod on the old WC heads that many of our boats came equipped with. Cheaper than buying a whole kit, and even those are getting hard to find. ---- john sandford via CnC-List <cnc-list@cnc-list.com> wrote: Hi Jason, Coincidentally, I had the same thing this spring. Completely removed the shaft log, cleaned it up, and replaced the hose and clamps. (Buck Algonquin Dont ship it by FedEx BTW) Partly as it was on the to do list, and partly because of a new shaft (1-1/8) and prop. The original packing was simply wound around in a one piece spiral BUT it worked like that for 30+ years. Didnt measure the size of what came out .my bad. Same thing as you, I used a calliper, did the math, bought ¼. When I tried to fit the packing in the nut, it would not go without a fight. I had to beat it into a rectangle, and then I only got 3 pieces in, as I had reduced the width, but then increased the height. A smaller packing would have gone in easier and after tightening the nut, the opposite occurred. I.e. increased the width, but reduced the height. 3/16 I should have used, and is now in my parts list going forward. As for the concern over 3 turns being enough. If the shaft log is 12 below WL, then the pressure on the packing is about 0.5 PSI. (An Engineer would give you 86 decimal places but directionally for every 2 ft head = 1 PSIG) So the pressure is irrelevant/diddley squat , we are not dealing with a through hull on Das Boot. 3 turns vs. 5 turns vs. 1 turn is irrelevant as long as it does the job. What IS important are the arrangement of the packing cuts and the tightness of the nut. Arrangement; Second Ring = 180 deg to the first Third Ring = 60 degrees to the second Subsequent rings = 60 degrees to the previous. Tightness; ALWAYS have a drip coming in. This will primarily indicate that you have a clearance of some kind that will prevent overheating of the shaft. If you dont have a drip, then you have no indication of the tightness range which could be anywhere from; Just above a drip to Im going to generate enough heat to either burn the packing or destroy the shaft or both. I dont know much about a lot of other tech stuff, but shafting, mechanical, etc. Yes I do. As a Marine Engineer , (an old one) I was trained on a ship with 42,000 SHP, 36 shaft and 4 square Flax packing. Took a full few days to clean out the old and fit new. (in Dry-dock of course) The above installation procedure was basic and the drip was checked every 2 hrs when underway. (Dont want to replace a burnt 36 shaft.) Submitted with respect of the knowledge/experience of others _______________________________________________ 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 --- This email has been checked for viruses by AVG. http://www.avg.com _______________________________________________ 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
