A traditional variety of shaft packing comprises a square cross-section rope made of flax impregnated with wax and lubricants. You must dig out ALL of the old packing. If it is hot to the touch it is too tight. In fact, with access to an infrared pyrometer, drip rates are much less important than they once were. I can't get enough leverage to move them. An alternative to conventional braided packing is Drip-Less moldable packing. With GFO they claim temps up to the 125-130F range are technically safe for the packing. Signs that the packing is failing and needs to be replaced are now easier to identify and can include any of the following: Stuffing box components are of stainless steel, brass or other application-specific materials.[3]. von-rohr.ch . Rich tried tightening the locking bolts, but couldn’t seem to get it just right. Its primary components are a threaded sleeve and a hollow nut through which the shaft passes. Overtime we started to notice that the bilge pump was running more than normal and we could see the stuffing box was dripping too fast. A turn of the adjusting nut compresses the shaft packing. It is not uncommon to see stuffing boxes leak at a much higher rate. When the box is full — but not so full that the adjusting nut doesn't thread on easily — adjust it to drip two or three times per minute, as previously outlined. A traditional stuffing box must drip, otherwise it will overheat, and wax and tallow melt at about 150°. Low-friction packing is six to ten times more expensive than flax, but because it rarely needs adjustment, it can be a good choice for a stuffing box that is particularly difficult to service. The gland nut allows the packing material to be compressed to form a watertight seal and prevent water leaking up the shaft when the tap is turned on. It is vital that the stuffing box does not overheat, since this will cause scoring damage to the shaft. The stuffing box should not be too hot to touch. 1911tex Sustaining Member. This drip, drip, drip of liquid is shown as the red drops oozing out of the Stuffing Box in the nearby pump schematic. There are improved shaft packing materials that aim to be drip-less when the shaft is turning as well as when stationary, also pack-less sealing systems that employ engineered materials such as carbon composites and PTFE (e.g. By Steve D Antonio. Presse-étoupe resserrable n Au cas où une fuite se forme au presse-étoupe, resserrer la vis de réglage dans un premier temps. We use cookies to enhance your visit to our website and to improve your experience. Retighten the packing nut to compress the flax around the shaft and slow the water drip rate. Because you remove the old packing before installing new, and it is the packing that is keeping the ocean out of your boat, it should be out of the water when you do this job. [2] Creating a proper plunger alignment is critical for correct flow and a long wear life. Sailing Totem: Bringing Holiday Spirit Cruising. Once the wax melts it drains out of the twine, starting a destructive cycle. Tightening the nut compresses this packing against the shaft, forming a watertight seal while still allowing the shaft to turn. Charter. December 4, 2008. Insert the wire into the bore and slide it against the bore surface until the "L" section slips into the flush port. With your wrenches on both nuts, hold the adjusting nut and turn the locknut clockwise to release it. It is not uncommon to see stuffing boxes leak at a much higher rate. Charter Provisioning in the Covid-19 Era. Curl one of your cut lengths into a ring around the shaft and push it into the stuffing box. Up here in Maine water is usually around 50ish-60ish in the summer depending on where you are, so I would think that is about the environment the box is seeing. It drips about 1 drip every two or three seconds while not running. Two or three drops per minute are adequate. Check your stuffing box regularly and provide it with the care it needs. If you must do it with the boat afloat, have the new packing ready to install as soon as the old is out, and drape a towel over the stuffing box to deflect the incoming flood into the bilge, where your bilge pump should handle it without difficulty. I acquired the boat in this condition 2-1/2 years ago. Do not run the pump blocked tight. At rest should not drip at all; while motoring a drip or two every minutes. Water is required to lubricate conventional packing, so a properly adjusted stuffing box can be watertight when the shaft is stopped, but it must drip when the shaft is turning. If your stuffing box leaks more than 8 drops a minute, it needs adjusting. drip rate seems about 1-3 per minute. Better yet, release each one and rotate it to view all sides before retightening. The packing nut never drips. Give threads and nuts a heavy coat of Boeshield T-9 (or some other corrosion blocker) to avoid this problem in the future. I have been getting water in the bilge lately and in looking for the leak found the stuffing box leaking. Now turn the adjusting nut clockwise until the dripping just stops. People. This nut fits three, some don't and it's not a huge deal if one does not fit more than two. The first step in stuffing box adjustment, then, is to figure out how to get two wrenches on the box--one for the lock nut and one for the adjusting nut — and how to position yourself so that you can pull on one while pushing on the other, and vice versa. Destinations. The shaft is wrapped by the packing and put in the gland nut. von-rohr.ch. Back this nut off a couple of turns. © 2020 Boat Owners Association of The United States. Likewise the shaft of a handpump or wind pump is sealed with a gland where the shaft exits the borehole. Again, a stuffing box should drip at a regular, albeit slow rate of between two and six drops a minute with the shaft turning. A proper installation strikes a balance between temperature and drip rate. If it comes out as shapeless wads of fluff, then measure the space between the shaft and the inside of the packing nut to determine the correct flax size. A stuffing box is an assembly which is used to house a gland seal. But this one is dripping constantly. This will allow the longest run-time possible before needing adjustment again. When adjusting the packing drip rate, follow the packing adjustment instructions, 1200504, to adjust as close to the 5 drips per minute as practical. When adjusting the stuffing box keep in mind that; if the adjustable stuffing box nut is too tight you will burn the packing which can end up with a damaged shaft. The linear seal around the piston rod of a double acting steam piston is also known as a gland, particularly in marine applications. He and his wife cruise aboard their 30-footer part of the year in the eastern Caribbean. Service Your Stuffing Box. It will also have packing nut threads or a gland nut. Slacken the compression nut and re-test until the drip rate and temperature are correct. After re-packing or adjustment, run the engine in gear for between 1 and 3 minutes, stop the engine and then (carefully) feel the body of the stuffing box. Vincent Daniello, August 16, 2012, https://en.wikipedia.org/w/index.php?title=Stuffing_box&oldid=979595908, Creative Commons Attribution-ShareAlike License, This page was last edited on 21 September 2020, at 16:46. If you don’t want any water in your bilge consider installing a dripless shaft seal in place of the stuffing box. This shaft had roughly .05" of stuffing box wear and was deemed "scrap metal" by the shafting shop. A special purpose heavy-duty rubber hose attaches the stuffing box to a stern tube, also called a shaft log, that projects inward from the hull. Two or three drops per minute are adequate. I go by how often bilge pump goes off, if I pump out before I anchor or moor & the darn thing wakes me up it's time to tighten the packing again. Learn More. A turn of the adjusting nut compresses the shaft packing. These inevitably corrode at the bottom, so you may need a mirror to check them. This doesn't harm the shaft or the stuffing box, but the spinning shaft will sling this excess flow all over the engine compartment, leading to rampant corrosion of the shaft coupling, the transmission housing, and everything else getting sprayed. The water is necessary to lubricate and cool the friction of the shaft turning, and without it the shaft will wear excessively. The one shown here is clearly starved for water and is overheating. Stuffing box temperature should not exceed that of the water in which the vessel is operating by more than 30°F-40°F. Other types of sealed connections without moving parts are also sometimes called glands; for example, a cable gland or fitting that connects a flexible electrical conduit to an enclosure, machine or bulkhead facilitates assembly and prevents liquid or gas ingress. Joined 7 Apr 2005 Messages 54. A common mistake is winding the new packing around the shaft as a continuous piece. The drip less kind which you can identify by seeing something like a 3/8" hose attached to a nipple on the stuffing box. Do this one clamp at a time. The sleeve — or sometimes the nut — is filled with rings of braided square flax rope that has been heavily impregnated with wax and lubricants. Don Casey has been one of the most consulted experts on boat care and upgrades for 30 years, and is one of the BoatUS Magazine's panel of experts. The stuffing box prevents sea water from entering the boat's hull. Proper compression allows about two drops per minute. If it does, give the packing nut another half turn and check again. If it is more than two, tighten the adjusting nut slightly. Tightening the stuffing box nut a half turn is all that is required to reduce the leak, but the location of the stuffing box can render this job far more difficult than it should be. Infrared pyrometers have changed the way stuffing boxes are adjusted, now it’s a measurable balance between heat and drip rate. 11 Apr 2005 #3 Y. yachtie8 New member. Maintain this gland around the prop shaft to keep leaks at bay. Ideally, the compression is just enough to make the seal both watertight when the shaft is stationary and drip slightly when the shaft is turning. On a boat having an inboard motor that turns a shaft attached to an external propeller, the shaft passes through a stuffing box, also called a "packing box"[4] or "stern gland" in this application. Add a third layer, then a fourth, each time staggering the joint. Water is required to lubricate conventional packing, so a properly adjusted stuffing box can be watertight when the shaft is stopped, but it must drip when the shaft is turning. When under way the drip increases a little. Marine-duty hose clamps secure the hose to the stern tube and the aft portion of the stuffing box sleeve. You can use pipe wrenches to turn the nuts, but adjustable packing nut wrenches tend to be easier to handle in confined spaces. A stuffing box is an assembly which is used to house a gland seal. If your stuffing box leaks more than 8 or 10 drops a minute, it needs servicing. One way the operator can know that the packing is not overheating is to ensure that the “drip rate” water is as warm as water used for hand-washing. More How To. When the drip rate is one or two drops per minute, stop the engine. Repacking Procedure. This is normal procedure. If your boat has inboard power, odds are it is fitted with a stuffing box to provide a watertight seal for the propeller shaft. Take care not to scratch the shaft with either tool. After the packing nut has been tightened a few times, the packing gets so compressed that it becomes hard enough to actually wear a groove in the shaft — a condition you want to avoid. In a common type of stuffing box, rings of braided fiber, known as shaft packing or gland packing, form a seal between the shaft and the stuffing box. I know this is bad and they need to be loosened along with inspecting the condition of the shaft so: 1. The most common example is in the head of a tap (faucet) where the gland is usually packed with string which has been soaked in tallow or similar grease. Charter . 13-JUL-2010.05" Of Wear. A sound stuffing box installation is critical to safety because failure can admit a catastrophic volume of water into the boat. The packing is inside the gland nut and creates the seal. This photo shows three rings installed. As it melts, the box starts to drip more, pointing to a lack of packing material. The drip rate must be at once sufficient to lubricate and cool the shaft and packing, but not so much as could sink an unattended boat. A properly adjusted stuffing box will have no drips when the shaft is stopped, but 2-3 drops/minute when the shaft is turning. It is not uncommon to see stuffing boxes leak at a much higher rate. ARC 2020 is Underway. I am pushing both wrenches downward to loosen them. The gland at the rotating shaft of a centrifugal pump may be packed in a similar way and graphite grease used to accommodate continuous operation. You do not want to twist this hose or twist the stuffing box inside the hose. CAUTION: Some stuffing boxes are rigidly attached to the hull, but most are connected to the shaft tube with a length of flexible hose. After you make this initial adjustment, you are going to need to check the drip rate with the shaft turning. New Charter Vacation Routines. Over time, operators will adjust the gland follower to maintain this drip rate. Sailboats may not need to have the packing replaced for five years or more, but when the stuffing box starts requiring frequent adjustment or if it begins to feel warm, it's time. Water is required to lubricate conventional packing, so a properly adjusted stuffing box can be watertight when the shaft is stopped, but it must drip when the shaft is turning. Operators should adjust their stuffing boxes periodically, by tightening or loosening the gland, to maintain a sealing water “drip rate” out of the back of the stuffing box. The other kind is the type I have and most popular which you have to pack with flax or Teflon cord. Multiply the diameter of your shaft by 14 to get the approximate number of inches you need for 4 layers of new packing — usually sufficient. Ron pointed out, as soon as you run or even just spin the shaft the rate changes. My stuffing box nuts are jambed tight. The drip rate must be sufficient to lubricate and cool the shaft and packing, but not so much as could sink the boat. Its a very important piece of machinery , but its often blamed for being troublesome or inferior to other types of propeller shaft seals . With the help of a flashlight — and a mirror if you need one — count the drops per minute. #: 3 Approved by: MCR 2 Date: 10June2003 Revised by: AAN 1200504 Operate the pump for 10 minutes at the highest normal operating pressure flowing sufficient water to prevent overheating. If you don't seem to have room for the fourth layer, hand tighten the adjusting nut to force the other rings deeper, then remove it again to see if this made room for an additional ring of flax. I adjusted mine this weekend, basically it was hand tight before locking. No part of the stuffing box or shaft adjacent to it should exceed more than 30°F above ambient seawater temperature, regardless of drip rate, while at any speed. [1] It is used to prevent leakage of fluid, such as water or steam, between sliding or turning parts of machine elements. Prepared by: TED Rev. Through tightening it onto the stern tube, the packing is compressed, creating a seal against the shaft. There is no reason why a well installed well greased stern glad should leak at … Tamp it evenly with a small dowel or a blunt screwdriver to push it all the way to the bottom of the box. The normal drip rate may vary between 5 and 60 drops per minute. Three Rings Installed . Don s/v Tellico. His books include Don Casey's Complete Illustrated Sailboat Maintenance Manual, and the recently updated This Old Boat, the bible for do-it-yourself boaters. The cooler your stuffing box runs, the longer shaft life you’ll have. In a common type of stuffing box, rings of braided fiber, known as shaft packing or gland packing, form a seal between the shaft and the stuffing box. General opinion seems to be that a normal stuffing box type should drip roughly once a minute when the shaft is running. Packing that is adjusted too loose can allow air to be sucked in through the packing during priming, reducing the height that at which the pump can be primed. von-rohr.ch. If a stuffing box is allowed to drip it allows for excellent cooling, longer shaft life, less opportunity for crevice corrosion and less opportunity for trapped air to run the box totally dry and cook it. *****CLICK BELOW FOR PAGE 3***** 17-DEC-2010. When this happens, the pump will need to be rebuilt, replacing at least the stuffing box and shaft. The drip rate must be at once sufficient to lubricate and cool the shaft and packing, but not so much as could sink an unattended boat. It should drip a few drops per minute when the shaft is turning, but no drips when in neutral. Two or three drops per minute are adequate. Packing installed this way will not seal properly. In many small fiberglass boats, for example, the stuffing box is mounted inboard near the point the shaft exits the hull. It must instead be installed as a series of stacked rings. In this position, mark the length of wire where it meets the top of the stuffing box. The stern gland or stuffing box as it is sometimes refered to is a much maligned piece of an inboard boats drivetrain. That hose supplies raw water to keep the shaft cool. The 60 drips per minute is a little more forgiving than the five drips per minute but should still be used as a limit for a maximum drip rate to be allowed. You will need to check this setting after the first couple of hours of use; some tightening is usually required. Even more disastrous, it puts an unattended boat at risk of sinking. Simply cut a piece of wire that is roughly the same length as the stuffing box depth, and then bend a short 90 deg "L" at one end. In principle a stuffing box is identical to the packing nut on a common faucet. Drip-Less packing requires two retainer rings of conventional packing. The easy way to do this is to wrap the packing around the shaft in some accessible location and cut across the overlap with a razor knife. Latest. Hold the packing nut while you release the lock nut, then unscrew the adjusting nut completely to open the box. In the real world, hydrocarbons can enter storm sewers after dripping onto the cement slabs that support the infrastructure of process plants. How to pack: Bend the new flax into rings around the shaft and press them into the stuffing box, staggering the joints between layers. 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Admit a catastrophic volume of water into the boat underway or with the shaft exits the hull the... Follower to maintain this gland around the piston rod of a flashlight — and a long wear.. The rate changes rather less when the shaft the rate changes stopped, but not so much as could the. Strikes a balance between heat and drip rate couldn ’ t want water! For Servicing your stuffing box sleeve while you release the lock nut, then push dripless packing into lengths just. '' hose attached to a lack of packing is compressed, creating a seal the. Couldn ’ t seem to get it just right premier temps your wrenches both...