N3522 Stuffing Box

I have to agree with Aquabelle. The drawing shows the "coupling" to have sort of a nipple shape at the junction with the stuffing box. Hard to see how the flange at the other end of the coupling can serve to compress the packing in that arrangement.

That said, several questions some to mind. It seems the diagnosis at this point is that there is come point where the shaft and tube have insufficient clearance to allow water to enter. From the drawing, hard to visualize where that might be. Normally, the only point at which the shaft is in near contact with the shaft is at the front of the adjusting nut. From your drawing it appears that you have an adjusting flange rather than an adjusting nut.

1. Is there water between the cutlass bearings? If all packing is removed, is there free flow of water at the collar (coupling?). It sounds like you have free water flow up to the stuffing box and none past that point. That would seem normal to me (other than the requisite desired "drip").

With the new packing materials...there is no "requisite" drip any more...often it will just look moist/ooze and stay cool...thus my reason to not have a burning desire for a "modern dripless" box.

Funny there's no injection unless the fiberglass shaft tube on the boat is pretty short...often the injection is as much about supplying oxygenated water to the shaft packing area to keep the shaft from corroding.

psneeld said:

Funny there's no injection unless the fiberglass shaft tube on the boat is pretty short...often the injection is as much about supplying oxygenated water to the shaft packing area to keep the shaft from corroding.

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I've heard that is also depends on the boat's speed. A faster boat creates more of a venturi effect and tries to draw water out of the shaft tube rather than let it flow in and circulate around. With the faster speed trying to draw water out, injecting water in at the stuffing box works with the venturi process rather than against it.

I believe John's boat is a semi-planing hull, and perhaps the first such hull that Nordhavn designed. Perhaps it's boarder-line between the two worlds of displacement boats with natural water circulation up to the stuffing box, vs planing hulls with water flushing fore to aft through the box and down the tube.

what I'm talking about has nothing to do with keeping water in the tube because of boat speed... it's abut stagnant water in there harming the stainless....I've heard but not have seen that some manufacturers are plumbing a/c pumps to them to keep the water in there oxygenated.

We found the problem (we hope)

Sometimes its the last place you look to find the gremlins! After a wonderful five days of sitting in the yard (weekend included) I finally picked up La Tempestad and took her home. I got the feeling we had abandon her when I checked on her Monday sitting in a corner, getting dirty and looking depressed (can a boat look depressed? OK, maybe I was the one depressed). During this visit the crew showed me the bronze compression plate and gland pieces which were in the back shop. With a pair of calibers they measured the inside fit (after cleaning up the corrosion build-up) and we only had .007 clearance. A call to the factory conformed the tolerance is .015 - .020. So, the combination of an out of spec fit along with corrosion build-up resulted in no water flow. This theory was previously confirmed when the crew removed all the packing and could not get any water to flow forward. After the compression plate was machined down and everything was cleaned up the boat was put back in the water without packing to confirm water flow. Packing was then installed and a short test run showed water dripping by the crew.
When I arrived yesterday afternoon the lead technician and I took the boat out for a test run and confirmed water dripping and temperatures were not climbing as fast. I paid the bill (north of $3K) set off into the sunset. OK, maybe not the sunset but did take the boat home. I made one check along the way and temperature was in the 90' with a little dripping. After reaching my slip I did one more check and temperature was 104 degrees compared to 119 degrees when I took the boat to the yard. Water was dripping strong and I think we may have found the fix. I realize I will need to let the packing set in and may run a little warm for awhile but "we have water flow". Owning a boat definitely offers you the opportunity to learn something new every day. Now I hope this journey is over so we can start to really enjoy the boat. I wonder if PAE will cover this 10 year old latent defect if we signed up for N4 (ha ha)?

John T.
La Tempestad

Greetings,
Mr. N. Well, I never.....I guess you DO learn something new every day. I stand corrected about my "Don't let them machine a thing" comment. Glad it all worked out in the end. Who would have thunk?

Is the stuffing box even made by Nordhavn? Or is it someone elses?

If they get their stuffing boxes from another source, I wonder if they mismatched parts or something...I have never heard of a regular old stuffing box with a similar issue.

Still sounds too strange...

I agree. They are normally just not about that sort of close tolerance...

BGlad (and anyone else): do you know the brand of the stuffing box shown in your photo at post #24? It looks just like mine, though mine is larger (for a 2 1/4" shaft). I have stainless drip-catch boxes under mine, with a drain line from these to a nearby shower-sump-pump box...so no drips into bilge

0.007" clearance still should have allowed water flow to packing gland. That is not that tight. Unless clearance was jammed with corrosion.

Corrosion Build-up

Ski in NC said:

0.007" clearance still should have allowed water flow to packing gland. That is not that tight. Unless clearance was jammed with corrosion.

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Corrosion build-up was an added problem on top of the tight tolerance. Took the boat out Friday for a short photo shot (yes she is for sale) and upon returning to the slip the temperature was still a little warm 104 degrees but 20 degrees lower then when I took her to the yard. Still need to the let the packing wear in bot so far so good. Keeping fingers crossed.

>007 versus .015-.020 is a big difference in my opinion.

Thanks to all.

Closest thing I could find was from Buck Algonquin. I thought I could search up several different types but they must be out of favor with all the dripless varieties currently available...

Bronze Packing Boxes - Rectangular Flange On Buck Algonquin

Aquabelle said:

BGlad (and anyone else): do you know the brand of the stuffing box shown in your photo at post #24? It looks just like mine, though mine is larger (for a 2 1/4" shaft). I have stainless drip-catch boxes under mine, with a drain line from these to a nearby shower-sump-pump box...so no drips into bilge

Click to expand...

Hi John T.
I followed your many posts regarding your two N boats and now see you own N3522. Could you send to me your direct email at power.boater@verizon.net
Thanks,
Greg Lee