Stuffing box advice

linedoctor

linedoctor

Well-known member
Joined
Feb 15, 2011
Messages
193
Fluid Motion Model
R-29 CB
Vessel Name
Mission Drift
The last couple of times I've been out, I've noticed that I'm getting a fair amount of spray coming from the prop shaft onto the walls of my engine compartment. I haven't run the boat with the engine compartment open to actually see where the water is spinning off the shaft, but from the pattern it looks like its coming off the shaft a few inches forward of the stuffing box.

Any quick ideas? I'm guessing its just an adjustment of something. I tried to find the issue on past posts but couldn't find the answer. Thanks!
 
I've notice something similar to this as well. It's just forward of the stuffing box located in rear of engine bay on the port side corner. The color is green with small black smudges in it. It's very slight and does appear now and then. I've been wiping it off but it reappears after a month or two of using the boat. I wipe it off as placing my shoe on it causes the shoe to slip badly and is a safety hazard for me.

The area where this green/black deposit occurs is certainly inline or at least very close to being inline with the stuffing box. My bilge water level beneath this area is always moderate/level and does not worry me.

I will be out on our boat for next 3-4 days so if I can remember about this I will look into the engine bay while underway to see if the stuffing box is the culprit.

Here's a snippet from http://www.boatus.com/boattech/casey/stuffing-box.asp

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. Two or three drops per minute are adequate. It is not uncommon to see stuffing boxes leak at a much higher rate. 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. Even more disastrous, it puts an unattended boat at risk of sinking. If your stuffing box leaks more than 8 or 10 drops a minute, it needs servicing. 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. Access can be especially challenging in boats with V-drives and in sailboats.

later.... 🙂
 
Thanks Barry,

Sounds like the exact same spot. Mine has progressed to throwing up enough water to soak a wiring harness about a quarter of the way up the side of the engine compartment wall and making a bit of a mess in general. Obviously soaking your electrical system with water is not such a good thing...especially salt water!
 
One of the reasons I'm considering having a dripless system installed such as the Lasdrop Gen II. Traditionalist think I'm being OC, but why have corrosive sea water being flung all around the engine compartment. With our electronically controlled systems I can't imagine the sea water is good for all the wiring bundles and their connections in the engine compartment. The larger yachts use dripless systems exclusively.
 
Boondocker: My issue isn't severe at all. There's no water as such being sprayed about in any quantity. Mind you, it could be 'early days' so it's something for me to keep an eye open for. If it were to get worse then I would first try tightening the stuffing box coupling to reduce water to just a few drips to return it to normal.
 
As others have said the packing nut should be dripping.

The rule we use is one single drip per minute when the shaft is not turning.

To prevent over spray, we cut the bottom out of a two liter pop bottle and slit it length wise
Then put it on the prop saft

Tighting the packing nut requires two wrenches typically a combination of a basin wrench plus a pipe wrench. This method over three boats hasn't worked that well for me - not super mechanically inclined

This time, phoned the factory got the exact packing nut lock nut size and had two wrenches made out if cheap steel

When tightening do not over tighten - potentially you can burn out the shaft

Watch for that one drip per minute
 
Hmmm -- when our boat is stationary there are no drips! I've checked for this many times and not a single drip is seen. The snippet I posted above indicates the stuffing box is water tight and therefore there are no drips when the prop shaft is not turning.

I have a shaft brush installed and maybe this collects, attracts or holds onto any water droplets from the stuffing box and lets them drop into the bilge. This brush sits on the exposed shiny part of the shaft between the stuffing box and the engine coupling. I will actually watch for this water dripping activity over next few days when we're out cruising for a short trip. I just need to make sure my two inquisitive Fox Terriers are unaware of what I'm doing as they always want to poke their wet noses to where I'm looking at. :roll:
 
To the best of my knowledge the stuffing should drip about one drip per minute when the shaft is turning. I helped Rich from Roam tighten his while we were together in Florida. We secured the boat to the dock and put it in gear and then observed the drip.
 
Conventional wisdom states your packing should not be dripping when the shaft is not moving.

Unfortunately these old-school flax packing systems are a "maintenance item". On previous boats we have been very happy replacing the flax with the goretex/ptfe packing rope which is nearly dripless and much cheaper than dripless systems.

On our C28 our packing nut was way too loose - so much so our bilge pump was cycling in port. We have tightened it down with improvement in symptoms.

Do yourself a favor and buy the correct wrenches (as others have mentioned: you will need two-the bigger the better) - its easy to accidentally rotate the hose on the shaft log if one is not careful. Try not to use heat to loosen the nut - the hose on the log would be the concern there. The packing locknut can be VERY tight. Ours is an early production boat - I wonder if they had a run of under-tightened nuts. Ours had verdigris'd into one mass... lots of "fixing words" were uttered addressing the leak.

To reiterate: make sure not to over-tighten as running a packing dry will score your propeller shaft $$$.
 
I am not sure why the water is being flung about. It sounds like it is working up onto the shaft more than normal and being spattered. Normally the drips will just fall straight down at the packing nut. Perhaps the packing is much too loose and there is actually a water flow rather than a drip.

Generally speaking the packing gland should not drip at all when not rotating but an occasional drip is not a big concern. Most recommendations are for 8 to 10 drips a minute when running at normal cruising speed. I generally have mine a bit more open than that with the knowledge that a bit more cooling of the packing can't hurt. I try to set it about 20 drops a minute. That is not enough to cause the pump to run frequently and not loose enough to drip when at rest.

My theory is the same as I used when building engines. An old-time mechanic told me about valves many years ago "When they're tappin', they ain't burnin!". People who were overly concerned about engine noise paid the price at the rebuilders later.

If you do enough research on "dripless" systems you will discover, as also learned over the years, that "All that glitters is not gold!". Packing glands have been around for many years and, if properly maintained, do exactly what they should do. And they almost never fail catastrophically.
 
I have a lasdrop dripless seal on my R25. Dry, no dries, just as they advertise.
 
I'm sorry I don't know the model number. The previous owner had the last drop shift log in the spare parts kit he gave me with the boat. I had it in a stall because I was on my way out of town. They charge me $75. It doesn't look like a difficult job but of course the boat has to be out of the water.

I've purchased several new boats over time and usually the manufactures open to making some changes during the build process.

For the small difference in price I would urge new owners to purchase a boat with the last drop install. I would also suggest they put the rebuild kit on the shaft when they install the last drop. The rebuild kit is only about three dollars extra and is recommended after 500 hours or so.

And while you're approaching about you facture for the last drop, I would urge the installation of an original equipment flow meter in the raw water supply to protect the edging that exhaust system in the event of a power failure.
 
You must log in or register to reply here.

  • Tugnuts.com is the community hub for Ranger Tug, Cutwater, and Solara owners. Since its inception in 2008, the Tugnuts forum has grown into an active and thriving community of more than 9,000 members. It serves as both a meeting place for the best boating community online, and an invaluable archive of information.

  • User menu
Back
Top