Shaft Seal for a Small Diameter Shaft and Stern Tube

[sailingjupiter]

I recently asked about the best shaft seal to replace the old stuffing box on my boat and got some great responses. I was looking to get a Volvo shaft seal. Cheap, reliable and got some good comments.

However when measuring up for the correct one, I have found that they don't make one small enough. I have measured the shaft and stern tube and found they are too small for any of the Volvo seals. Also looking at the PSS etc they also don't go that small. My measurements are -

Prop shaft - 20mm
Stern tube - 35mm

I assume they are mm rather than inch size. The boat is an MG Spring from 1989. Engine Yanmar 1GM10.

Anyone know of a dripless seal that would fit. I assume that the Volvo is just too big as theirs start at 25mm. 5mm is a big gap for this type of fitting. Or does anyone know any different?

They made quite a few Springs and there are thousands of 1GM10's out there. So what has everybody else got?

Any solutions to this little problem out there??

Thanks again for the help.

 

[Cloven]

I used to have a PSS seal fitted to my Hunter 272 which had a 7/8" shaft on a GM10. Just looked at this website:

http://www.shaftseal.com/

and they do the PSS down to 22mm. Might be worth giving them a ring and see if they can help.

 

[pvb]

[ QUOTE ]
Also looking at the PSS etc they also don't go that small. My measurements are -
Prop shaft - 20mm
Stern tube - 35mm

[/ QUOTE ]PSS make a 20mm shaft version, with stern tube sizes of 1.25" or 1.50". Your 35mm stern tube (1.37") might be able to fit into either of these - you should ask whether the 1.25" will stretch to fit, or whether the 1.50" can be compressed satisfactorily.

 

[pampas]

If your stern tube is the BORE stated, why not get a shaft made to fit the smallest seal made, or sleeve the shaft to suit seals ?

 

[Norman_E]

If the 1.5" seal will not compress down to the tube size all is not lost. The tube can be built up in overall diameter with a piece of 1.5" tube stuck on with araldite. It might even be possible to achieve a good fit just by wrapping self amalgamating tape round the tube.

 

[Relax]

Hi,

I just fitted a Volvo seal to my Sadler 25. It has a GM10 with a 25mm shaft and a tube about 36/37mm - I assume this is the same as yours with a 35mm bore?

The stern tube is no big deal - I sleeved mine with the old rubber tube from the stuffing box patiently pared down to fit. I fitted this first with a jubilee clip at the back end then fitted the Volvo seal over (a stretch even so) and compressed the clamp.

I think your shaft is a bigger problem - the cutless bearing on the inside of the seal also bears on the shaft to centre it, not just the lip seal so any sleeving would need to be about 75-100mm long and a very exact fit. No idea how you would fix it - really need to be positively locked, not just glued. I would think therefore this would need to be machined to fit?

Just waiting to see if mine floats or sinks upon launching.........

 

[PCUK]

Stick with the stuffing box and maintain it properly. No future problems and no additional cost!!!

 

[Eygthene]

These people www.lakesterngear.co.uk/ supply a range of flexible sleeves and shaft seals. They supplied a sleeve for my non-standard new GRP sterntube to match it to my greased bronze and double lipsealed sterngland for my 25mm shaft.

The flexible sleeve needs to be proper reinforced flexible hose, with a corrugated section to allow flexing when the engine vibrates and a good fit and very securely clamped to the sterntube (with a generous length of engagement) as well as to the sterngland. I use two jubilee clips at each end.

Be very wary of any kind of makeshift fixing here, as it can easily slip off and your boat will start to sink very quickly if it does. You may find yourself in a very inconvenient situation if you need to refit it whilst underway.

You may be much better off, as advised above, to retain the existing stuffing gland and to renew the packing.

 

[FAITIRA]

When I bought my present boat, it had, has a "Deep Sea Seal", touch wood!, it has not given any trouble, but I would, myself, never have fitted it in place of a conventional stuffing box. As a live aboard, I could deal with a problem with a stuffing box afloat. A serious problem with this thing would inevitably involve a dry out alongside hopefully (if in tidal waters) or expensive lift out if not!

 

[Tranona]

Your biggest problem will be the 20mm shaft as the normal minimum now is 25 mm or imperial 1 inch. I have not seen any seal to fit 20mm, so repacking the existing stuffing box is probably the only way to go. If it is done properly and the shaft is not worn it is reliable and long lasting - even if it has to drip a bit to keep cool

 

[pvb]

[ QUOTE ]
I have not seen any seal to fit 20mm...

[/ QUOTE ]As posted above, the PSS seal is available for 20mm shafts.

 

[roger]

I bought a "Stopelo" seal some years ago in a Dunkirk Chandlers. It was cheap compared with UK ones and easy to fit. Its the standard Stainless ding round the shaft with a corrugated rubber pipe with graphite ring. Stopelo had a website - try Googling it.
Ours has worked perfectly for at least 5 years.