Dry bilges

[Squeaky]

Good morning:

I have been annoyed for over 26 years because I have yet to find a shaft/greaser system to stop the ingress of water around the prop shaft.

I first tried the Deep Sea seal followed by a couple of packed stern glands but in every case water still entered. Sometimes it was only for a while until the grease "settled" but as soon as I ran the engine in gear I had the same problem.

I suspect that the Deep Seal system eventually failed because of misalignment of the engine.

My question is this "Am I asking for the moon in expecting to find a system that will keep the bilge dry?"

If you have achieved this result, what system do you have installed?

I aim to have another run at this in the spring and would welcome suggestions.

Cheers

Squeaky

 

[vyv_cox]

On the extremely rare occasions that I find any water in the bilge it is cause for investigation. I used a conventional packed gland stuffing box for years, it never dripped. I then changed to a PSS to avoid the regular greasing required with my packed gland. That has never leaked either. When water does enter it has come variously from the water pump cover, water pump shaft seal, heat exchanger cover seals and loose hose clips.

 

[Tranona]

Three types of shaft seals that will minimise drip to the point of almost non-existence. PSS face type seal that Vyv uses - same principle as Deep Sea Seal but properly designed and made. Tides Marine which uses lip seals in a housing on a tube similar to flexibly mounted stuffing boxes. Simplest and cheapest if you can fit it is a one piece moulded rubber seal with water lubricated integral bearing and double lip seals made by Volvo.

Pros and cons of each are regularly debated here. But all work if properly installed and choice might depend on specific installation and availability.

 

[Norman_E]

My boat has a Volvo rubber seal that does not leak, despite the fact that the first season I had the boat I did not "burp" it on launch. I did have some water in the bilges, which I have now traced to a leak from the seal on the raw water strainer, but I was able to prove that the shaft seal was not leaking by fitting a plastic paint roller tray beneath it.

 

[KellysEye]

Stern glands should drip to keep it lubricated, about two drips a minute. We have a steel boat so water in the bilges is an absolute no go. We have a plastic bowl cut to fit under the gland with one of the above water bilge pump hull fittings epoxied to a hole in the bowl. Then a hose goes to an old oil container which we empty occasionally.

 

[overstag]

Or buy something with a saildrive next time...... (I know, I know).

 

[Martin_J]

As Tronona says... The plain and simple Volvo shaft seal.

Mine never dripped and was only replaced after six years because that's what was suggested. The complete part was less than £50 and was even fitted whilst still in the water. (OK - I did get a couple of pints in then...)

http://home.att.net/~beneteau331owners/tipsaddons/volvoshaftseal.htm

 

[Quandary]

One of the more dopey requirements of BW inspectors is the provision of a weir in front of the engine. They believe it will keep oilspills away from the bilge pump so that they will not be pumped into the canal. They have not worked out that oil floats on water and can get anywhere. My current boat has a saildrive and is therefore bone dry, with a massive bund under the engine, at least 4 times the oil capacity, moulded as part of the grp engine bearing framework, but on an earlier one with a run through bilge from prop. shaft to bilges the weir proved very useful in trapping water where it could be easily mopped up when checking the engine oil, so the bilges stayed dry. The weir I made was just a bit of 63mm x 12mm painted timber shaped to fill the gap between the front engine mounts then fitted and sealed with a fillet of adhesive sealant or epoxy. Being (very) old school I always liked my conventional shaft to drip slightly through the stuffing box when turning, I found that if it was bone dry it tended to get warm to touch.

 

[Tranona]

Stern glands should drip to keep it lubricated, about two drips a minute.

Not so. That only applies to some conventional stuffing boxes with greased packing. The three designs I have suggested should not drip as the seal is specifically designed not to pass water. They only drip if the seal needs replacing.

Suggest if you want dry bilges in your steel boat (at least preventing water ingress through the shaft seal) you replace your stuffing box with a more modern design.

Not that there is anything functionally wrong with a properly maintained stuffing box - just that they drip water!

 

[alahol2]

My stuffing box has been going for 30 odd years and hardly ever drips. I usually only need to sponge the bilge every couple of months. I suspect a sterntube full of grease keeps most of the water out.

 

[Bosun Higgs]

Would be worried if I ever saw any water in the bilges. Current boat has a Volvo seal and previous ones have had lip seal type seals. Never used a stuffing box, but they are designed to leak a bit to keep cool.

 

[alahol2]

Never used a stuffing box, but they are designed to leak a bit to keep cool.

Been thinking about this one. Do you (the members of the forum) think that the original designer of the stuffing box thought 'Ah, better make sure a bit of water gets past this water seal to keep it cool' or did he test his final design and find it still dripped a bit. He then turned this slight fault into a feature?
When he added a greaser to the system was he not trying to stop those last few drips?
I know it's always quoted as received wisdom to allow drips, but if a non-dripping, greased stuffing box doesn't get hot then why should it be made to drip?
Or maybe I should just stop thinking too hard about these things.

 

[vyv_cox]

the original designer of the stuffing box

Which came first, the stuffing box or the drip? The very first pumps, Archimedes and other types about 5000 years ago (???) must have leaked badly, probably with virtually no seal at all. First move must have been to wrap a rag around the shaft, leading to some sort of housing to hold it in, and so the stuffing box was born. Water leaking out was never a problem and it still does today on non-critical duties. Only when powered ships arrived did the need to be drip free become more important but quite recently it has been normal to pump ships every hour to cope with shaft seal leakage. No doubt it soon became known with flax and similar natural materials that if it was tightened up so that no water got through it would heat and burn in a short time. Only now that we have more self-lubricating materials is it possible to achieve drip-free stern glands.

 

[Breadbin]

Good morning:

I have been annoyed for over 26 years
Squeaky

Dang, beats me. I've only been mildly irritated for about 10

 

[WoodyP]

I think that many of the stuffing boxes that leak are poorly engineered. If properly made, there is no reason why a stuffing box should drip.

 

[alahol2]

I think that many of the stuffing boxes that leak are poorly engineered. If properly made, there is no reason why a stuffing box should drip.

I think it more likely that people adjust them so that they DO leak because that is what everyone tells them to do.

 

[30boat]

I think it more likely that people adjust them so that they DO leak because that is what everyone tells them to do.

I was under the impression that they must leak in order to stay cool and lubricated.

 

[chabrenas]

Have you actually checked the alignment? Can you perhaps see evidence of misalignment when the engine is running? It doesn't take much to put side loads on the seal, Though I believe modern seals are more tolerant than traditional stuffing boxes.

 

[noelex]

Another completly dry bilge with a PSS seal.