Shaft Packing Bah!!

[Maynard Rupp]

I decided to re do the shaft packing with Gore Tex GFO material. We had the boat out over the weekend to re-paint the bottom. (That is another story). I read my Hatteras owners manual which provides a nice drawing and says the packing is 1/2''. The GFO packing company makes a nice listing of required sizes for different size shafts. Their data also said I want 1/2" for our 13/4" shafts. Sure enough, when I remove the old packing it is smaller than 1/2". I made my rings, then flattened the stuff with a hammer so it would slide in. When we launched it was dry. I idled out of the Miami river and downtown area. When I got to Biscayne Bay, I went below to check on my packing. I burned my hand pretty bad when I touched the stuffing box. I limped to our slip. I now plan on spending another bag of bucks to get the 3/8" packing that I should have had in the first place. Lots of bad information in the world of boat maintenance. I am going to re-pack while the boat is in the water. Pascal says it is easy, does anyone else have an opinion or a trick to do the job easily?

 

[captddis]

The 36 takes 3/8. I prefer to pack in the water. The incoming water helps to flush the old stuff out and you can adjust the log the way you want and run it in at the dock if desired. Packing on the hard you have to guess at the adjustment.

 

[SKYCHENEY]

I've repacked in the water before. Let's just say that it's not for the faint of heart. As the water comes gushing in you're inclined to work FAST. Don't worry though, Maynard, you'll get it done. I did.

 

[yachtsmanbill]

Its no big deal Maynard. Have the new rings cut and flattened and all the tools at the ready. Water coming in isnt really too bad until the last ring is out and the first new one is back in. The fresh 1/2" should come out real easy so thats a plus.
I just packed mine on the hard. I put a good squeeze on it for an hour or so, then backed off everything till loose, and then locked the nuts. The trick is with any packing, to let it run in and seat (glaze) before any adjustments are made. Twice a week we used to go around the plant and pull up on pumps and valves, and we would adjust them 1/2 a flat on the nuts, go have a smoke, come back and make another 1/2 flat. Sometimes it took an hour to get a good adjustment. You always adjust UP to no leakage, never let it get dry and then try to loosen it.
When youre done, spend a few hours running around making SMALL adjustments. ws

 

[the kuz]

Maynard, you will be happy when you get done. I did our 36C with gortex 3 years ago when we in put new diesels. Put 600 hours on with out a drip at rest. Just made the first (1/2 flat) adjustment a few months ago. We did add engine water cooling lines to the stuffing boxes, and I think that also has helped reduce packing wear. It's easy to do and keeps everything nice and cool at higher RPMs. Changing packing in the water is not bad - just get everything ready and in reach before you remove the old packing.
Regards, Bob K

 

[Brian Degulis]

You might try loosening it up (very loose) and reversing for a little while to see if you get flow. I know you have the wrong size but even with the correct size if you tighten the gortex to much and stop water flow just loosening it isn't enough to get water flowing. With gortex I hardly tighten at all untill I'm running and leaking then just enough to get a slow drip when moving. If it's been packed in there hard it takes a bit to get it to loosen.

Brian

 

[Maynard Rupp]

Maynard, you will be happy when you get done. I did our 36C with gortex 3 years ago when we in put new diesels. Put 600 hours on with out a drip at rest. Just made the first (1/2 flat) adjustment a few months ago. We did add engine water cooling lines to the stuffing boxes, and I think that also has helped reduce packing wear. It's easy to do and keeps everything nice and cool at higher RPMs. Changing packing in the water is not bad - just get everything ready and in reach before you remove the old packing.
Regards, Bob K

Thanks, our 36 already has those little tubes to the stuffing boxes from the engie seawater system. I was told that the tunnels create a reverse flow around the area where the shafts exit, so they put those tubes in to insure a flow of water to mthe packing.

 

[Maynard Rupp]

Thanks all. I will do that re-pack tommorrow. What really angers me is the bad information in my Hatteras Owners manual. The other bad data is the battery identification in that manual. Our house battery went dead and I changed the forward 8D battery, which the book said is the port engine/house. I still had to use the parrellel start switch to crank the port engine. We disconnected the ground on that new battery, and the house lights still work. Now we know that our batteries are reversed from the manual. The real head problem I have is that I would swear they were correct several years ago. How could that change? No, the positive cables can't be switched as they won't reach. How else can that occur?

 

[LENZ]

Thanks all. I will do that re-pack tommorrow. What really angers me is the bad information in my Hatteras Owners manual. The other bad data is the battery identification in that manual. Our house battery went dead and I changed the forward 8D battery, which the book said is the port engine/house. I still had to use the parrellel start switch to crank the port engine. We disconnected the ground on that new battery, and the house lights still work. Now we know that our batteries are reversed from the manual. The real head problem I have is that I would swear they were correct several years ago. How could that change? No, the positive cables can't be switched as they won't reach. How else can that occur?

Maynard, Mic the bore of the stuffing box and then mic the o.d. of the shaft subtract the o.d. of the shaft from the id of the stuffing box then divide your answer by 2 that will give you exact size of packing needed. I have come across a few stuffing boxes that were not a nominal size (somebody machined for some reason?) as far as repacking your boat in the water, just leave the first ring of packing in and add the new it worked for me. After repacking, a drip or two from the stuffing box is a good indication your packing is getting lubricated. It should take a week or two of adjustments before it's just right.
LENZ

 

[REBrueckner]

Maynard, how about removing the positive cable from your "house bank" to confirm whether the house lights work from that battery/bank.

Then disconnect positive cables from each battery/bank until the house lights actually do extinguish. At the point the lights go out, begin reconnecting positive cables to other batteries to assure they stay off.

I can't think of any way a supply from one battery can be switched to another other than by (a) switch or (b) changing positive cables (c) Electric Panel reconfiguration. Whereas a 12 volt dc ground is permanently tied together at a single point, often a connection terminal on an engine(s), positive wiring is kept separate via separate cables to engine and genny starters and separate bus bars in the dc electric panel for accessories.

This may sound silly, but you didn't user jumper cables for some purpose and leave them connected? I carry a pair aboard as back up and for charging other people's batteries and in an emergency aboard my own boat.

 

[Pascal]

the rule 2000 in each bilge had no problem handling the flow, not even cycling on 50 / 50

let me know if you need help tomorrow... moral or otherwise... -)

 

[Maynard Rupp]

Thanks Pascal. I think I can handle it OK now that I have had all these great inputs. I did not mike the ID of the stuffing box, but I was at the Ft. Lauderdale Sam's Marine office. They looked up the build sheet on our boat and they have the dimensions of our specific shafts and the ID of our stuffing boxes. The shafts are 1.75" and the Id of the stuffing boxes is 2.5". the 3/4" difference when divided by 2 means 3/8" packing. I can hardly wait to twist my sorry old body around those things tommorrow. Thank god they still make Advil.

 

[Maynard Rupp]

OK, the job is done and now is correct. I adjusted the packing for one drip/ minute. I just wish we had better data available in the boating game. Every source including my owner's manual called for 1/2" packing. The correct size is 3/8", which is what I have now installed. The incoming water was no big deal at all. Thanks everyone for your advice on this project.