Packing gland

[dwkerch1]

On my 1987 Marine Trader Sundeck I cannot get the packing gland set for a consistent through-flow. With*an adjustment for*8 - 10 drips per minute at rest I*normally get a similar*through-flow at*my*typical*cruise setting of 1600 RPM, but when I accelerate to1700 - 1750 RPM*through-flow ceases unless I loosen the gland, and I have not been able to get any through-flow at power settings over 1750 RPM. Has anyone else experienced this problem and/or have any ideas how to solve the problem?

 

[Keith]

You might not see a drip at higher speeds, but the water may be coming in and spraying off the shaft. Have you checked to see if the area is wet around where it normally drips? With that much leakage at rest, you should have some coming through when underway. What type of packing is in there?

 

[dwkerch1]

I'm running graphite impregnated cotton packing. I don't see any moisture from a spray from the stuffing box and when through-flow ceases the box gets*warm enough that I can't hold my hand on it for more than a few seconds, which is too hot. I tried*teflon packing a while back*and didn't see any difference.

 

[Keith]

Yea, that's too hot. You can repack, but don't over-tighten right off the bat. You need to pack it, run it, then gradually tighten it until you have it the way you want.

If that's not working, you may have a burr on your prop shaft, but I haven't heard of situation like yours... most installations that leak static don't stop when underway.

I use Gore's GFO packing and it works great! Install it and tighten it up gradually. It's dry at rest, had a bit of water coming through underway, and keeps cool. No graphite involved, which is a good thing. See: http://www.gore.com/en_xx/products/sealants/packing/gfo_packing_fiber.html *and http://www.stuffingboxpacking.com/ *or http://www.e-marine-inc.com/products/gfopacking/packing.html

 

[dwkerch1]

I ran across information on the Gore product when I last repacked in '07, but went back with the material I had on board. I checked it out again, with*the links you sent, and I'll try it this time. Thanks for your input.

 

[FF]

The gore tex or its competition can be tightened enough so it does not drip underway.

The stuff needs no cooling water drip , and a look see with the heat gun after a day underway leads me to believe that it even lowers the shaft temperature.

The shaft is warm from the engine space, the stuffing box is the same temp or usually cooler.

Works great in the rudder stuffing box too.

AT $65 a lb it aint cheap tho.

FF



-- Edited by FF on Thursday 2nd of July 2009 04:12:27 AM

 

[Capn Chuck]

I have a question, you say you tried Teflon packing then went to graphite. Did you do the re-packing and are you certain you removed all of the old packing before replacing? The engine compartment temperature is not going to have anything to do with the water lubrication or lack there of, in the packing gland. Chuck

-- Edited by Capn Chuck on Thursday 2nd of July 2009 08:55:40 AM

 

[dwkerch1]

Yes, I did the re-packing myself, shortly after purchasing the boat and*while*she was on the hard. I removed all of the old packing, which was graphite, and completely cleaned the box out.*I dug*a lot of small pieces of old packing*out of*the bottom of the box when I cleaned it out. Thinking back on finding the old pieces of stuffing, it's*probable that stuffing had been added over time, not replaced, and I'm wondering if some of the small pieces of old packing may have been pushed through the bottom of the box, and still be lodged against the shaft?

 

[Capn Chuck]

dwkerch1 wrote:

I ran across information on the Gore product when I last repacked in '07, but went back with the material I had on board. I checked it out again, with*the links you sent, and I'll try it this time. Thanks for your input.

So I assume you plan to repack again. Be sure ALL of the old packing is out including little bits and pieces and any marine growth inside. Once repacked with the Gore packing, do not overtighten, you want a steady drip once back in the water. Let the shaft turn for a while then slowly tighten until you have a drip every ten seconds under way. At that rate you will probably have no drip at rest but maybe a little. Another adjustment after a few hours of running will probably be needed. You need to always go from loose to tight and never tight to loose. The packing will take a set and that may be your problem. Chuck

 

[FF]

Having used flax and teflon I think the Gore material is far too soft to, "The packing will take a set", ever have this occur.



It reminds me of silly putty with stiffeners and can almost be crushed between fingers.It does the job as we now use it in what I consider the hardest service.

Our 90/90 has a stuffing box that is ALSO the stern bearing. 18-19 wraps of material create the shaft bearing and serve as packing.

This was done so the bearing could be serviced if needed while out on a cruise in any anchorage. The prop is a wide bladed 2 blade prop of 19 inches diameter that is held hidden/prop locked behind the deadwood while sailing.

The blades pop out from behind the deadwood 800 times a min , the loads are VERY cyclical, and it works great, no dripping required.

Before this the cooling requirement required a remote cup grease fitting and line to the stuffing box. When thru sailing the noise of the slow dripping would be silenced with a turn or two of the grease cup.

Still installed , but not in use any longer.


FF

 

[Capn Chuck]

FF, Once again you make statements that are just not correct. The Gore material will take a set like most others if not more so. This fellow has a traditional stuffing box and problems already without getting inaccurate advise. His packing should never be "wrapped" and probably will take a max of three sections cut to a single wrap of the prop shaft with the cut ends offset from each other. It sounds like he has packed the stuffing box before so probably already knows this. The Gore packing has no resemblance to silly putty. You are simply confusing the issue more. Chuck

 

[FF]

"wrapped"

Hopefully he understands EACH wrap of any packing material will cut indivually , and EACH inserted and pushed into place , before the next.

A split piece of plastic pipe is required for our 18 turn bearing, but with care the 3 or 4 rings in a std stuffing box can be done by hand.

To do as suggested here

"probably will take a max of three sections cut to a single wrap of the prop shaft with the cut ends offset from each other."

Chop a ring into 3 sections to create a single wrap is something I have never seen advised.

Why would one do this strange procedure? Or is English a second language?

 

[Capn Chuck]

FF, This may be something you never advise but this is how the rest of the world, the packing manufacturers and the folks that build the stuffing boxes all recommend, and how I, and most other experienced marine techs, have done on thousands of boats over almost 40 years without one issue. I see nowhere in my post where it says to chop a ring in three sections to create a single wrap, so perhaps yes, English is your second language. Chuck

-- Edited by Capn Chuck on Saturday 4th of July 2009 09:10:48 AM

 

[Marin]

FWIW the yard we use in Bellingham continues to recommend the standard old flax packing material, and they prefer it over the Gore and other products. They do use Gore packing on things like rudders where the rotating motion is very slow (they didn't explain their reasoning-- I'm just repeating it).

But our boat had flax packing when we bought it and it was replaced some nine years later only because we had the shafts pulled for truing in one case, replacement in the other, so they took the opportunity to replace the packing. Our packing glands are conventional although the shaft logs have water feeds from their respective engines to assist the cooling and lubrication of the cutless bearing(s) in the log. One gland needed tightening one time in the nine years that elapsed before it was changed, the other needed no adjustment at all during that time. The boat is used year-round. When running there is a sheen of water around the entrance to the gland where the shaft goes through but if they drip they do so at an interval far longer than I've been willing to sit there and wait through. They have never dripped when the shafts are stationary.

So based on our experience, I've been impressed with the performance of plain old flax. I'm not saying that Gore offers no advantages--- it may be very advantageous on boats with shafts that turn a lot faster than ours. But flax has not proven to be the low-tech, ineffective, old-fashioned material it's often portrayed to be. Based on our experience, we followed the yard's recommendation and had the glands repacked with flax. So far, so good.

Both glands have always run cold to the touch.

 

[FF]

But flax has not proven to be the low-tech, ineffective, old-fashioned material it's often portrayed to be

The hassle with flax is it will pick up flakes of metal from the turning shaft , and capture the pieces to use as a grinding material, eating groves in the shaft.

This seems to be more common on SS shafts than bronze , at least on boats we have repaired.

As the Gore material is far softer , it can be used on damaged shafts.

We have used emery cloth strips to "shoe shine" the scored shaft , to get rid of sharp edges in the scored section , to allow a boat to finish the season. Some folks got 3 years , before needing to repack.

 

[Keith]

I put my Gore GFO packing in when I replaced a scored shaft in 2001. After initial run-in, it's still in there, and has required tightening maybe 3 times, each less than 1/8 turn. Dripless at rest, just a fine mist underway. That's pretty damm reliable and maintenance free. And a heck of a lot cheaper than those "dripless" shaft seal systems.

 

[FF]

"And a heck of a lot cheaper than those "dripless" shaft seal systems."


LOADS , as most folks Refuse to follow the instructions and replace the bellows as part of a maint routine.

A burst bellows will usually allow more water in than dual bilge pumps can dewater.

The danger of these dripless contraptions is far beyond any "convienance."

Install proper materials good for a decade , or SINK??

you choose!

 

[Nomad Willy]

The dripless seals are only 2 or $300. In recent years I've had nothing but and I'm almost 100% satisfied. On the carbon fiber and sleeve seal one needs to make an extra effort w the set screws. Use two and make the dimples on the shaft quite large. Then use locktight. Our sleeves slid twice on us and there was enough water in the fore cabin that stuff was floating above the floor and part of the floor was floating too. One can put radiator hose clamps ahead of the sleeve to act as a retainer. But other than the above all my dripless seals have performed perfectly. I like the fact that some of my sea water for engine cooling is injected into the stern tube and feeds plenty of water to the stern bearing. The bellows are quite tough so I'm not worried about them at all. I wouldn't have an OMC stern drive though. I think Marin's right. Plain old stuffing box w plain old flax is just fine. Even though I have the high tech stuff I think this is something that didn't need reinventing. I'll bet most greif w stuffing boxes comes from over tightning the clamping nut. Oldfishboat has a point too. Some engine mounts are very soft and allow fore and aft movement of about 1/4". Should a shaft slide forward the flutes of the stern bearing may be blocked. Also cutting the packing at a shallow angle and stagering the radial position of the ends of the packing about 180 degrees could help the seal so only light clamping pressure from the nut is required. But if your'e really pissed at your old stuffing box get a dripless** ..* they work fine* .. too.

Eric Henning.

 

[FF]

I like the fact that some of my sea water for engine cooling is injected into the stern tube and feeds plenty of water to the stern bearing.

And should one engine crap out , how do you get feed water to the windmilling propeller shaft?

 

[Marin]

FF wrote:


And should one engine crap out , how do you get feed water to the windmilling propeller shaft?

in our case, we don't. I attached a strong bracket/shackle arrangement to a heavy floor beam directly above each shaft coupler.* If we have to shut down an engine I simply wind a line around the shaft coupler a bunch of times and then tie it off to the shackle directly over it.* Works great.

I suppose one could get fancy and put together a plumbing and valve crossover arrangement that let the water feed from one engine go to both shaft logs but that seems a lot of hassle for something that probably won't occur very often or ever.* Easier to simply tie off the shaft.*

Besides, even without a water feed if you have BW Velvet Drives you're going to have to tie the shaft off anyway unless you're going to be towed at very a very slow speed, say 4 knots or less.* The VD manual states that VD transmissions can be freewheeled safely only at low speeds.* They use the terms "trolling or sailing" to describe these speeds.

*

 

[Keith]

Freewheeling a BW velvet drive is fine up to at least 8 knots... I did it for years on my last boat with BW's approval. No ill effects. This is when I ran one engine and shut the other down.

 

[marinetrader]

Rip out the flax packing and replace it with GFO Packing, its vitually dripless. It will not heat up weither.

I have it in mine and love it.

Mike

 

[Knotinahurry]

I have adjusted many packing glands on may types of vessels and would suggest that your glad nut should not leak when stationary, and only leak when rotating and set to the recommended drip specifications. The main objective is to ensure adequite cooling this can be verified by ensuring the shaft is running cool to warm under load, too hot can damage the shaft. Always adjust the packing with the engine under light load with the shaft turning, this will require at least two people.

 

[FF]

The glad nut should not leak when stationary, and only leak when rotating and set to the recommended drip specifications.

That's the proper old way for Flax packing or teflon .

NO Drip is ever needed with modern GFO.