Repacking Stuffing Box - Page 2

Wanna-b · 09-23-2019, 05:40 PM

When someone says to adjust underway....you don’t mean with the shaft spinning do you? I would assume you tighten...put in gear for a bit, take out of gear, then re-tighten if needed. Is that correct?

jimisbell · 09-23-2019, 05:50 PM

DO NOT...I repeat DO NOT try to adjust it while the shaft is spinning. That is a good way to kill yourself or lose a body part. Who said you should adjust it underway? They are NUTS, I said replace the stuffing IN THE WATER, NOT UNDERWAY. You cannot work on a spinning shaft that has 150 HP driving it unless you have a death wish.

STB · 09-23-2019, 06:17 PM

I've often ended up adjusting it, taking it out for a sea trial, shutting down the engine, fine tuning it, restarting and re-evaluating, and repeating as necessary.

The packing seems to need to run to break in. And, I have a tendency to set it too loose at the slip. So, by running it, I get to break it in and see how much it drips at cruise.

I wouldnt want to loosen the lock nut underway for fear that it'll loosen up and, when I go to adjust it, I'll keep losing my reference.

Regardless, I think the person giving that advice was likely talking about an fine tuning adjustment after a test run, or with engine off between segments of a test run.

Cheers!
-Greg

Wanna-b · 09-23-2019, 06:22 PM

Hahaha, thanks for the replies. I am a fireman and immediately thought making the adjustment while under way was a sure fire way to end up in the ER.

OldDan1943 · 09-23-2019, 06:26 PM

Whilst in the US Navy, we were told to tighten when we had docked for a period of time (undefined) and loosen it prior to getting underway.
Was it done? Daymned if I know. I was in the engine room.

Northern Spy · 09-23-2019, 06:53 PM

I'll go inform every millwright and industrial mechanic I've ever worked with that they are doing it wrong.

But you have a point. If you are not comfortable with doing this, then don't.

Quote:

Originally Posted by jimisbell

DO NOT...I repeat DO NOT try to adjust it while the shaft is spinning. That is a good way to kill yourself or lose a body part. Who said you should adjust it underway? They are NUTS, I said replace the stuffing IN THE WATER, NOT UNDERWAY. You cannot work on a spinning shaft that has 150 HP driving it unless you have a death wish.

psneeld · 09-23-2019, 07:05 PM

Quote:

Originally Posted by Wanna-b

When someone says to adjust underway....you don’t mean with the shaft spinning do you? I would assume you tighten...put in gear for a bit, take out of gear, then re-tighten if needed. Is that correct?

Not reallly....one must realize working around moving parts has it's dangers, but on mant boats no big deal..

You just have to make that call, but adjusting a few fittings while the shaft is turning can be daunting or no big deal.

OldDan1943 · 09-23-2019, 07:23 PM

IF you insist on adjusting the shaft packing glad while the shaft is turning, remove all loose fitting clothing and I recommend, you do not undertake this without someone watching you.

rslifkin · 09-23-2019, 07:47 PM

Personally, I tend to adjust mine with the shaft just freewheeling slowly (engine being adjusted in neutral, other engine idling in gear to maintain steerage). Although I have done it idling in gear as well. Never above idle and in my case, the stuffing boxes aren't in my engine room, they're behind the bulkhead. So they're both accessed from floor hatches directly above them making it pretty easy to safely reach in there and adjust without getting caught up in moving parts (no spinning coupler bolts nearby to snag on, for example).

psneeld · 09-23-2019, 07:57 PM

Of all the dangerous things we do in boating, never thought tightening stuffing boxes as up there...be careful but not paranoid.

jimisbell · 09-23-2019, 10:13 PM

Quote:

Originally Posted by Northern Spy

I'll go inform every millwright and industrial mechanic I've ever worked with that they are doing it wrong.

But you have a point. If you are not comfortable with doing this, then don't.

Yes, that really wasnt what I was talking about. I work on lathes and you couldnt get anything done without it spinning....LOL

syjos · 09-23-2019, 11:44 PM

Been adjusting packing while underway for 35+ years without mishap. It's the easiest way to get the adjustment just right. Especially using the moldable dripless packing.

I currently have the gland type that has two threaded rod adjusters with two nuts each. Only require two combination wrenches to loosen and adjust.

A lot safer to adjust than:

The type with the very large nut and lock nut requiring two oversize open end wrenches to loosen and adjust.

And that adjustable wrench in the picture, sold as a packing nut adjustment wrench, is totally useless and dangerous around spinning shafts because they slip so easy. They were originally designed for plumbing.

My previous boat had the big nut gland and I adjusted it underway. I was younger and dumber then. I would not adjust that type underway now.

rslifkin · 09-24-2019, 07:24 AM

Gland type is another good point for safety of adjustment. Mine are neither of the pictured types, they're just 1 big nut with ears. They get locked in place with a cotter pin through each of the ears and a corresponding hole in the flange on the stuffing box. The big nut can sometimes be turned by hand, sometimes it takes the big wrench.

pmcs · 02-10-2021, 02:25 PM

Mainshiptom, Can you verify that your single shaft is 1.75" ?

Thanks !