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joeniver 24-12-2019 18:11

Pan-Pan for a hurting boat!
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Where the propeller shaft connects to the transmission on my Yanmar 3HMF it is leaking salt water. I tasted it!

The flow goes from a slight stream to a 2 second drip. It changes from fast to slow drips*if I twist the propeller shaft while holding the large nut.

The large fitting in the picture seems to be leaking the water. The shaft is what goes into this fitting.*Would I be able to just hold the shaft and tighten the large nut so that it screws more onto the threads that are visible?

And would this stop the dripping?

Is this what is called the cutlass bearing?


a64pilot 24-12-2019 18:16

Re: Pan-Pan for a hurting boat!
Most will call that a stuffing box.
Rather than to try to explain how to adjust the thing, this is a good link.
I believe you need to adjust yours and not necessarily repack it, but the article should explain what you r looking at

Wotname 25-12-2019 02:20

Re: Pan-Pan for a hurting boat!
^^ what a64 said +1

Also called a stern gland.

JPA Cate 25-12-2019 17:47

Re: Pan-Pan for a hurting boat!
If it turns out you're out of packing--it wears out--try the teflon packing. It worked really well for Jim and me on our previous boat. The nut then required only to be finger tight. Didn't drip.


a64pilot 25-12-2019 17:50

Re: Pan-Pan for a hurting boat!
I’ve had the Teflon packing for three years now and other than right at first, I’ve not adjusted it since, it’s totally dry at anchor and underway a ring of water will form but no drips and it runs cool.

joeniver 25-12-2019 19:06

Re: Pan-Pan for a hurting boat!

Tightened up the nut by less than one turn and the dripping mostly stopped. Next time I motor I will put a temperature gun on it. If it is too hot I will loosen it a bit.

From what I read it needs some water--not air--to keep the packing moist. If air does get in there, I need the drip to push the air out so it is just water. Temp should me less that 110 degrees Fahrenheit.

So I am not freaking out when I hear my bilge pump go on once in a while.
My boat is in the water and I did not want to take the packing out.


a64pilot 25-12-2019 19:38

Re: Pan-Pan for a hurting boat!
No harm with a temp gun, but I’d say no more that 25f more than water temp, which can be 110 or so in warm water.
Really most of us say if it’s not uncomfortable to hold continuously, it’s OK.

I keep contemplating a dripless myself as to be truthful I like gadgets, but I keep running into articles like this and just don’t.

Alan Mighty 25-12-2019 19:57

Re: Pan-Pan for a hurting boat!

Originally Posted by a64pilot (Post 3043318)
I keep contemplating a dripless myself as to be truthful I like gadgets, but I keep running into articles like this and just donít.


The concluding para in that story says it all and endorses a dripless/packless shaft seal:

"However, from my perspective as a trawler owner and towboat operator, a brand new dripless shaft seal, properly installed, will do exactly what the manufacturer claims it will do: provide a vibration-tolerant, drip-free stuffing box. Be sure to read and follow the manufacturer's installation and maintenance instructions, and keep the literature close at hand so that it will remain in your mind as you perform routine maintenance in your trawler's engine room."

a64pilot 25-12-2019 20:05

Re: Pan-Pan for a hurting boat!
You just ignored the parts about how fool proof the standard packing is I guess and went straight to the so they won’t sue me part.

CaptTom 26-12-2019 05:18

Re: Pan-Pan for a hurting boat!

Originally Posted by a64pilot (Post 3043325)
You just ignored the parts about how fool proof the standard packing is I guess and went straight to the so they wonít sue me part.

My first thought was that Passagemaker just wanted to protect it's advertising revenue. But you're right, it may have been the lawyers who had the last word, not the sales and marketing department.

That part about scrupulously following maintenance instructions, along with the admonishment to keep the procedure handy in the ER probably says a lot, too.

tkeithlu 26-12-2019 06:36

Re: Pan-Pan for a hurting boat!
The only problem I've found with the most popular of the shaft seals is that it was delivered with a very weak soft plastic hose for the water injection from the raw water pump. Since failure of that hose would result in flooding, I replaced it with reinforced rubber hose. I've never had a drop of water from mine in 1,000 engine hours, but I'm going to inspect it today.

A traditional stuffing box has the safety advantage of leaking a little when it leaks - catastrophic leaking is unlikely. As a beginner, I tended to tighten the stuffing box too much, trying to get rid of the last drops.

a64pilot 26-12-2019 07:29

Re: Pan-Pan for a hurting boat!
I was pretty sure I wanted dripless, I mean who wants water in their bilge, even if mine is about four feet deep amd can hold lots.
Then three years ago I had my shaft pulled to be shortened and checked for run out and had them go back with Teflon packing, I wasn’t there so I don’t know if they used the hard to find actual PTFE packing or the much more available Teflon impregnated flax, but to start with it had no seepage at all, and as you can imagine got fire cracker hot within the first hour when I checked it, so I backed off on it so it would drip a little. Then as it was running cold slowly tightened up until now it runs cool still but no drops at all, and it’s not been adjusted for three years.
So other than spending about $750 and having to plumb in a water hose to the dripless seal, what advantage will I see?
Plus it seems that my dry bilge is transitory anyway, it seems that something happens every few months to put some water in it, last time it was flushing my engine cooling system for instance.
Now once the bilge picked up an odor, it stank. That was traced to it being full of fresh water, it seems that where we were showering in the cockpit had water running into a cockpit locker, that drained to the bilge.

But other than that one time, which had nothing to do with a shaft seal having a couple of inches of water moving around in the bottom of the bilge hasn’t been an issue.

What bothers me is there have actually been several near catastrophic failures of dripless shaft seals, and maybe some sinkings, once sunk how do you know what sunk it? How do you deal with that hundreds of miles from the nearest haul out and no Boat US or USCG etc?

Many of those failures are the PSS seals when the rotor backs off from loose locking screws, they seem to have solved that issue I think with their “Pro” seal that has a locking collar as a back up. Or I believe that’s what it’s for, even if it’s advertised as another purpose of course, cause if they admitted what its for then they are admitting to a design shortfall. Unless I’m mistaken that locking collar is available to purchase, if I had a PSS seal. I’d be buying that locking collar right away and eliminate one problem.
Lot better answer than a hose clamp in my opinion.

But it seems the worst failure mode is the bellows tube tearing, and it would take me 20 min of emptying my supply room to get to it to rig a temp repair, or I assume you could wrap it with a towel and maybe hose clamps and slow the leak to a small one anyway.
So the hose having to be a bellows means it has to be flexible and that means weak compared to that strong stiff Buck Algonquin hose I have on my stuffing box, it would take a huge amount of force to tear it.

So that takes us to if you want the hose to be tough, it can’t be a bellows.
So what about the Lasdrop GenII seal? I’ve never even seen one, but it does seem to address both weaknesses of the PSS seal, and yes I know the PSS seal is the most popular.
I assume the Lasdrop hose is stiff and strong, cause it can be?

tomlisasail 26-12-2019 12:32

Re: Pan-Pan for a hurting boat!
Thanks for the link, I copied it and will take it out to the boat. I need to look at my DSS with article in hand. I guess I was part of the set it and forget it crowd (actually the mechanic set it). As always you're an encyclopedia.

Shrew 26-12-2019 14:44

Re: Pan-Pan for a hurting boat!
Your tongue is not an appropriate sensory input method for troubleshooting mechanical issues in the bilge.

KP44 27-12-2019 07:26

Re: Pan-Pan for a hurting boat!
Magellan may have tasted the water to find the Straits of Magellan, thus avoiding Cape Horn and finding passage to the Pacific. But we should never do a "taste test" with bilge waters. A sick skipper is dangerous to the ship.

The cutlass bearing is at the propeller end of the shaft.

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