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 From: Ainslie [mailto:ains...@hay.net] Sent: May-10-18 9:47 PM To: cnc-list@cnc-list.com Subject: Stus-List Stuffing box material Hello, The stuffing box on my 35 Mk 3 had a steady drip last fall, so I repacked it recently. According to my callipers, I could use ¼ flax in the gland nut (1 shaft). This seemed to pack in easily enough, but I was only able to get three rings in and still have enough threads on the nut. However, I had pulled four rings out! Theres no way I could get four of these quarter-inch rings in. My question: have I made a mistake should I have used 3/16 material? As I mentioned, the packing seemed to fit into the gland fairly easy with just finger-pushing, but could this overheat the shaft, and are three rings enough? Launch is next Wednesday, so Id have to move quickly if I need to downsize it to 3/16. Thanks! Jason Ainslie, Spirit 1984 C&C 35-3 Bayfield, ON
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