DIY stuffing box spray shield

I noticed that I have a scum stripe in my bilge in line with the drip from my stuffing box. The wood underneath the engine room decking (removed for the picture) had been soaked with salt spray over the years, as apparently was the surrounding area. The shaft coupling was just wire brushed and repainted because of the heavy rust.

It might only be a cosmetic issue, but I decided to reduce the area that might be subject to salt spray. I cut the bottom off of a little plastic bucket (old drywall spackle), made a hole and a slit for the shaft and two holes for the packing gland bolts. It is just a jam fit, easily removed when it comes time to repack the stuffing box.

Well done.
I have suggested covering the shaft/stuffing box interface many times to catch and stop the spray which will travel damaging wood but worse, rusting any nearby steel parts including the engine back, the engine mounts, the gear box, corroding wire connections and so on.

We had those stuffing boxes in our last boat. Why not move to a packing like Duramax and get rid of the dripping all together?

Even though I use the Gortex GFO packing I still cover the actual interface between the stuffing box and the shaft.

I do not tighten so far as to stop all leaking but very close. It takes many running hours to get any bilge buildup.

The cover prevents the spray from even that tiny weepage from travelling around the engine compartment to cause rusting of nearby components.

I still suggest a cover even with these near miracle packings. Once rusting starts it is not easily stopped.

Nice idea!

I use a plastic bottle such as a 1qt or larger size with with the pour end cut off, a split up the side to a hole cut to fit around the shaft. I also use a smaller water bottle size around my raw water pump in case the seals leak. The outboard water pump is difficult to get to and see if it leaks. Sorry I don't have any photos as the boat is 1k miles away.

Tator

Comodave said:

Why not move to a packing like Duramax and get rid of the dripping all together?

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Because over tightening Duramax so that there is no drip is not recommended, even by Duramax (which I use).

The effect of saltwater in my engine room was also shown on the rear of the engine and front of the transmission, directly below the heat exchanger anodes. It looked like years of changing anodes had resulted in saltwater dripping on the engine/tranny during the change and that had eaten through the paint and caused rust. I cleaned that up, spray painted, and now use a piece of plastic bag to direct any drips into the bilge when changing anodes.

I also had an area under the raw water filter on the engine room floor that was covered by salt crystals. It kind of looked like frost. Years of pulling the filter out and cleaning it on the aluminum diamond plate had pitted the surface. Lots of freshwater and Salt Away cleaned that up. I now have the lower half of a 5-gallon bucket underneath the filter to catch the dribbles when cleaning the Groco filter.

The weird thing about saltwater is that it never dries up. It just waits for enough moisture to come back to life and start corroding again.

I don’t see anything in the instructions that says you can’t tighten it to no leakage. In fact it says you can tighten it to the desired leakage after the initial break in.

Comodave said:

In fact it says you can tighten it to the desired leakage after the initial break in.

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It seems you have chosen your "desired leakage" to be "no leakage whatsoever," but I'm not sure that is a valid interpretation of the DuraMax instructions.

A few drops of water in my bilge is easily handled by several bilge pumps, so I can let my Duramax drip. My "desired leakage" is probably a few drops a minute, but it doesn't matter to me whether it is three or seven, i.e., whether my bilge pumps once a week or every other week.

For me, dripping is less of a problem than what I have seen of the damage caused by an over tightened packing gland. I'm always surprised when I see the cost of a new SS prop shaft, forgetting that it is the yard fees that are the killer.

Well, if there needed to be some dripping I would suppose that Duramax would specify the minimum number of drops per minute. So since they don’t say a minimum and they do say set it to your desired leakage then I believe that zero drips is acceptable. Also on our last boat we had the same stuffing box as the OP. They yard had packed it with Duramax 7 years before I bought the boat. The boxes were not dripping at all so I asked them if they were tightened too much, they said no that they always set them to no drips after the break in period. About 3 years after I bought the boat I had the engines out so I rebuilt the stuffing boxes. The shafts were in perfect condition where the packing was. So that packing had been in place for 10 years at that point and if the packing being too tight was going to damage the shafts I think it would have shown up in 10 years.

I snug the Duramax packing to zero drip at the dock, then check with an IR thermometer gun while operating at cruise rpm. The stuffing boxes (pressure fed from the engines) consistently run at 5-10F above sea water temperature when at that setting. No wear the last time I pulled the shafts.

Duramax says that it will run hotter than regular stuffing and is supposed to. It will use the stuffing box as a heat sink to remove the excess heat.

Dave, do you have a hose from the riser feeding water to the stuffing box. I do and for that reason do not think the stuffing box needs to drip as it is kept wet. Without that feed of water I would want to stuffing box to weep water.

Yes, there was a hose for cooling water.

I'd definitely expect that to make a difference. For those of us who don't have any water force-fed to the stuffing boxes, they're more likely to need some drip to keep things cool and happy regardless of the packing used. Lower friction, better packing materials will just need less drip (but still some).

I used a Forgers plastic can

The PO used a Gatorade bottle. It works good enough that I left it on there 8 years now.

Tator said:

I use a plastic bottle such as a 1qt or larger size with with the pour end cut off, a split up the side to a hole cut to fit around the shaft. I also use a smaller water bottle size around my raw water pump in case the seals leak.

Tator

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I also use the split plastic bottles to catch any spray, I’ve managed to fit a low sided utility box under each stuffing box to catch and contain any spray residue, this way I can monitor how much is leaking and what is “other” bilge water.