Prop Shaft Leaking

[STG]

Help….? My prop shaft has started leaking into the bilge. It is leaking at the rate of about 2 gallons per hour forcing me to have to pump every 6-8 hours to keep water level low.

I have attached a picture. There is a 2-1/2” (+/-) pipe with threads on the outside that come through the hull. This is not leaking at the through hull penetration. However, the shaft goes through this pipe and has some bronze(?) fittings that slide over the smaller shaft that is coming from the engine and they cap the larger pipe. (See green caps). The water seems to be coming through the very end fitting where the actual small shaft goes through the first cap.

Big question is, do I have to haul to fix? I assume so, but with no experience in this issue, maybe there is a trick I do not know? What are all the caps at the end of the large pipe? I assume holding in some sort of seal/bearing type item?

Does anyone have experience repairing this problem?

Thanks,

Steve

[Target9000]

Have you tried tightening your stuffing box with a couple of wrenches?

[GordMay]

See Main Sail’s excellent photo-essay “Re-Packing A Traditional Stuffing Box”
➥ Re-Packing A Traditional Stuffing Box Photo Gallery by Compass Marine at pbase.com

This can be done in water (no haulout).

[STG]

Originally Posted by GordMay

➥ Re-Packing A Traditional Stuffing Box Photo Gallery by Compass Marine at pbase.com

This can be done in water (no haulout).

Thanks Gord. That is what I was hoping for. I glanced over the link you attached, and it sounds fairly straight forward. However, when I remove the old packing, wouldn’t the water start flowing pretty quickly? How do you do this while still in the water? Or maybe you just work around it and keep the bilge pump going?

[STG]

Originally Posted by Target9000

Have you tried tightening your stuffing box with a couple of wrenches?

I will definately try this first. Thanks. I didn't want to mess with anything until I heard from a few people and no one shouted "don't touch it". This sounds like a typical leak that can be dealt with without hauling (hopefully).

[motion30]

You have all your new packing cut to size an work quickly Some like to leave the last ring of old packing in place to keep the leak to a minimum. I have done this many times with no problem Perhaps you can have someone with experience help you, once you see it done It will be easy for you

[Vasco]

I repack in the water. Surprising little water comes in but I usually wrap the shaft at the shaft log (the thing the shaft goes through) with a strip of bicycle inner tube rubber ( a rag might do just as well) and nothing comes in.

[GordMay]

Originally Posted by STG

... when I remove the old packing, wouldn’t the water start flowing pretty quickly? How do you do this while still in the water? Or maybe you just work around it and keep the bilge pump going?

Some water flows, so you work reasonably quickly. Even so, the inflow isn't that great, over a few minutes.

[DeepFrz]

STG, do you know how much to tighten the packing nut and how to check it?

Servicing Your Stuffing Box by Don Casey

[bazzer]

Originally Posted by GordMay

Some water flows, so you work reasonably quickly. Even so, the inflow isn't that great, over a few minutes.

Hate to tell you, my packing box lock-nut came loose whilst motoring and the packing nut slipped forward, water came p*ssing in. Of course I was able to get it back together pretty quickly, but I was surprise how quickly the water came in.

[Vasco]

Does the water come in faster underway than stopped?

[osirissail]

If your boat is located someplace where the water temperature is reasonable - you can go over the side and dive down and wrap the prop shaft and shaft log from the outside with some plastic or other material including a towel. That will stop or greatly reduce any water flow up through the shaft log. Then you can take your time removing, cleaning and installing new packing. Then go over the side and remove the temporary material from the prop shaft and log.

[STG]

Originally Posted by DeepFrz

STG, do you know how much to tighten the packing nut and how to check it?

I don’t, but I did skim the link you posted and will read more carefully as I get ready to try. Thanks.

Originally Posted by Vasco

Does the water come in faster underway than stopped?

I believe so. I had been looking for the source of the leak for a few days, and after a couple trips out and about the water seemed to be coming in faster, so I that made me suspect it. I couldn’t see the water dripping under the shaft, so I missed it before. It definitely has gotten worse the last couple times out, so maybe things are just loosening as the prop turns? The boat seemed to need a lot of catching up on maintenance though, so it is likely time to repack.

Originally Posted by osirissail

If your boat is located someplace where the water temperature is reasonable - you can go over the side and dive down and wrap the prop shaft and shaft log from the outside

It is cold (PNW 55 deg or so). However, I do have a drysuit, and scuba gear. This may be a good safety net so I that don’t feel so rushed and can do it right and have more exposed area inside to check things out. Thanks for the tip.

All: Thanks for the input. As usual, I think I made this out to be worse (in my head) than I needed to. Better to be safe than sorry though.

[Target9000]

As a first move, I'd try to just snug up the packing nut first. See if that slows/stops the the leak. Don't over tighten it. It needs to drip a little water while you're motoring to keep from overheating. If that "solves" the problem you might be able to make it until you haul out (if doing it anytime soon). If that doesn't work go ahead and repack it.

[STG]

Well, I really appreciate this site and the great advice I have been getting. I couldn’t tighten the stuffing box anymore, as it turned out there were only two rings of packing inside and it was as tight as it was going to go. In reading the link that GordMay posted, it indicated that most have room for at least three rings, so I put that many as the package had plenty of material, and it stopped almost as soon as it was hand tight. A little extra twist of the wrench and it withstood a few minutes of running the prop in forward and reverse at dock. Problem seems to be solved. I will take it out for a spin today and see how it holds up.

One bonus takeaway was the recommendation in the link to stay away from WD40, etc. and it suggested using “PB Blaster”. As I already had some WD on hand, I tried it first but could not budge the nuts. After going to two stores that were sold out of PB Blaster (something I have never even heard of) I found some at an auto parts store. This stuff worked like magic and in minutes the parts broke free fairly easily. Great stuff. I HIGHLY recommend it.

Thanks again for all the advice. I slept much better last night without having to dangle my leg over the side of the bunk.

Steve