Stern glands

[Whitelighter]

So Seralia is the first boat I've owned with shafts and therefor sternglands.
I have recently started to get a reasonable amount of water in the engine bilge but this is isolated to when the boat is underway. Prodding around under the shaft I can see some residual dampness around the starboard side so I think this is the source (they all run into the lower bilge)

So I know they require maintenance, but I honestly have no idea what (everyone tells me shafts are easier).

I've attached a poor pic (the gland is covered by a stainless steel plate). They also seem to be cooled, there is a pipe that connects to a fitting with a cock forward if the sterngland aft of the v drive box)

So do I tighten them to stop the leak, or is it a case of lift and replace something?

 

[kashurst]

edit sorry didn´t read your post properly as per Portofino (long day small children etc), if its your stern glands you probably just need to tighten them up a tad. 1/2 a turn on each nut and see if the drip stops. If not 1/2 a turn more and so on. Its important to keep the pressure plate fairly parallel else it may touch the shaft and drone. On previous boats I have had with similar glands I used to let them drip while the boat was in use and then tighten just enough to stop the drip when I left the boat for a few weeks or months. From the picture it looks like yours may not have been adjusted for a while. Give the threads and nuts a really good soaking in wd40 or similar and leave overnight before tweaking them.

I would, if you have time, actually undo the nuts both sides a lot and get some water proof grease on the threads then do them back up and adjust the tightness. This will help you get a "feel" for how compressed the packing is - it should be easy to stop the drip with little force on the spanner.

If you find you need to adjust the nuts quite often, or its hard to tighten the gland nuts, they will need to be repacked. Not hard to do but probably best to do it when its out of the water if you haven´t done it before and the nuts, bolts etc haven´t been moved for some time.

 

[Portofino]

My inclination would be research it all a bit more .
Water can run from a long way and settle under a "suspect"
Eg from a poor bow - window seal running down inside out of sight ,when under way water spray up splashes and the boat is bow high so once in the boat it ends up under /between an engine .
Another example is a duff push fit joint or some other plumbing issue -agian it may be remote from where the running attitude moves it back .
Have you tasted if ?
Have you eyeballed the seal when underway ?

 

[Seastoke]

Jez is not the pipe lube does it go to oil tank or water

 

[Medskipper]

It is my understanding that stern glands are designed to leak a little when under way. This is to cool the friction of the shaft against the glands so no need to worry about a bit of water. It's more dangerous to over tighten them. They should not drip when the shafts are not turning, so watch them when stationary and if they are dripping then slightly tighten the nut on each side by the same amount. When the boat is on dry land it's worth withdrawing the plate and checking to see if they need repacking/greasing.

 

[superheat6k]

Many think simple stuffing box glands like these are the best, but over time they will form a groove in the shaft, and changing the packing can be very difficult if access to the companion plate (the part that pushes into the packing) is difficult for instance just to adjust the tightness.

I have similar on Boadicea, and fancy changing them when necessary to PSS, as I prefer a dry bilge, but for now I have to nip them up 1/4 turn every 3 months or so to stop the drip.

Details of the PSS at www.pyiinc.com where you can identify the size needed. The stationary rubber part can mount to the companion plate which in turn is mounted to the stern tube the wrong way around, bearing in mind this needs to be sealed to the front face of the stern tube with a gasket and suitable sealant, such as sikaflex.

The sizes needed are the OD of the shaft and companion plate outer to which the rubber bellows will mount, and look for emperic sizes, e.g. neat fractions of an inch ( 1 3/4" or 1 7/8" etc) or likely 5mm intervals if metric (45 or 50mm etc.).

A good UK supplier is Aquafax.

 

[Bandit]

The stainless plate over the stern gland is to stop grease and water being sprayed over the space the shafts are in.

Stuffing boxes ie packed seals are horrible things.

In the photo it looks like the front plate of the stuffing box is corroded as are the nuts.

I would look at fitting new stern seals this winter that leave the space dry.

I am not keen on PSS seals and much prefer Tides Marine seals see http://www.tidesmarine.co.uk/products/propeller-shaft-seals Speak to the UK Office really Knowledgeable and helpfull, also fit a spare "O"ring seal ahead of the seal so you can fit a new seal without releasing the coupling.

To fit a new stern seal or to remove the existing seal clean up and inspect you will need to have the boat out of the water, release the coupling by the gear box and draw the shaft back to inspect the shaft for wear and fit the new seal.A Tides marine seal or a PSS will require a salt water feed from the engine to cool them, not difficult.

Tides Marine Seals are the mutts nuts.

 

[john_morris_uk]

No idea what the anti PSS bit is all about. We've had PSS seals on our last two sail boats and I've seen them on many of the power boats I use and I've never had a moments bother with them. Dry bilges and they look after themselves.

Other modern seals are available....

 

[Deleted User YDKXO]

No idea what the anti PSS bit is all about. We've had PSS seals on our last two sail boats and I've seen them on many of the power boats I use and I've never had a moments bother with them. Dry bilges and they look after themselves.

I'm not sure whats wrong with PSS seals either. I have them on my boat and so far have performed very well. On the other hand I have had a major problem with a Deep Sea Seal which IMHO is a rubbish design and I wouldn't have on any boat I owned. The Tides Marine seal is a good design and worth considering

 

[oldgit]

If water lubricated thought that about 1 drip per second was the accepted norm while underway . ?

 

[Sandmartin]

Stern seals are simple and effective. When running a very slight leakage is occasionaly acceptable - but not desirable. Anything leaking should be grease. When you stop, turn the greaser until pressure is felt, and there should be no leakage. If you have any serious leakage then your shafts are bent of props unballanced.

 

[Bandit]

Traditional packed stern glands allow water and grease into the boat as well as causing shaft wear.

A modern seal such as a Tides Marine Seals leaves a dry grease free bilge, it can have a second seal mounted ahead of the seal for future use, just remember to prove the water supply from the engine its only a small aperture at both the engine end and the seal end of the supply line. Its easy to test the temperature of the stern seal with a laser thermometer or by putting your hand on it.

When I bought my current boat it had Deep Sea Seals which are now outdated, the spring goes from the rubber and the seal is no where near as strong.

I am just not keen on PSS seals and the way they work, a colleague who handles all our shaft and stern seal work had two year old PSS Seals in his boat which was not comfortable with and he fitted Tides Marine in their place.

 

[Whitelighter]

Just lifted the boat for a prop scrub and everything visually ok under the boat, though the short run to the crane and back did add to the bilge water.

Going to try tightening the bolts after a good soak in wd40

 

[Bandit]

Traditionaly packed stern glands:

Every Few Years they will need re packing which is a bit of an art in itself.

They need to drip to keep cool.

Occasionally say every 10 years or so the shaft will need drawing, the stern glands need removing de greasing and blasting to inspect the bare metal of the stern gland then either refitting or fitting a drip less seal. This is a good time to also replace the cutless bearings in the "p" brackets and stern tube and to check the alignment.