Dripless Shaft Seal Inspection & Maintenance?

[Dockhead]

I have a dripless shaft seal on my boat. It is the type which has a raw water feed from the main engine. I have never had one of these before -- always had normal dripping seals with packing which needed regular fussing.

It has never given me a moment's trouble, which worries me (seems not normal for anything on a boat not to cause some problem sooner or later). It will soon be 12 years old (my boat was commissioned in 2001); about 1500 engine hours.

My boat was out of the water over the winter, and I had a reputable marine engineer inspect it, plus the steering gear, rudder bearings, and rudder seals.

He lubricated and adjusted the steering cables, but pronounced everything else to be fit for service.

What to watch out for with these? Can they really last this long? Do you guys inspect your seals? What to look for?

[Bash]

Originally Posted by Dockhead

What to watch out for with these?

Watch for when they start to drip.

[Dockhead]

Originally Posted by Bash

Watch for when they start to drip.

Is that all? Sounds far too simple. ..

[Bash]

Originally Posted by Dockhead

Is that all? Sounds far too simple. ..

I suppose it's also a bad sign when they begin to glow in the dark.

[delmarrey]

PYI's (PSS) recommends replacing the bellows every 6 years, but 10 years is not unheard of. If yours is a PSS I'd be looking into a bellows change.

PSS Shaft Seal

[sww914]

I had a boatyard friend who, if the normal adjustment wouldn't stop the leaking, would slide 1200 grit wet sandpaper between the carbon and stainless blocks, and gently sand both sides for a few minutes. He said that he had 100% success with only one exception when the carbon was cracked on one.

[Dockhead]

Originally Posted by delmarrey

PYI's (PSS) recommends replacing the bellows every 6 years, but 10 years is not unheard of. If yours is a PSS I'd be looking into a bellows change.

PSS Shaft Seal

I'm at 12 years, as far as I know. The bellows look like new, but I guess this is good advice.

[Quintessa]

I replaced mine at 9 years and they looked fine in the boat. When we pulled them out they were at end of their life and glad to replace them. Would well and truly be replaced them now and soon than later.

[Dockhead]

Originally Posted by Quintessa

I replaced mine at 9 years and they looked fine in the boat. When we pulled them out they were at end of their life and glad to replace them. Would well and truly be replaced them now and soon than later.

The reputable marine engineer I paid to inspect mine might have told me that, eh, while I was still on the hard?

Can it be done with the boat in the water?

[noelex 77]

I replaced my PSS when it 9 years old.
Compared with the new one the bellows had lost some of their elasticity and spring, but it looked a long way from any risk of catastrophic failure from the bellows tearing.


PSS recommend every 5 years. I think they are being very conservative, but if it is now 12 years old I would replace it at the next haul out.

Its not a job that can be done in the water.

On some boats the prop, needs to be removed to slide the propshaft back far enough.

Keep oil and grease away from rubber bellows.

[Kestrahl]

Originally Posted by noelex 77

I replaced my PSS when it 9 years old.
Compared with the new one the bellows had lost some of their elasticity and spring, but it looked a long way from any risk of catastrophic failure from the bellows tearing.

PSS recommend every 5 years. I think they are being very conservative, but if it is now 12 years old I would replace it at the next haul out.

Its not a job that can be done in the water.

On some boats the prop, needs to be removed to slide the propshaft back far enough.

Keep oil and grease away from rubber bellows.

i had mine off two days ago with the boat in the water. was able to slide the shaft back enough to take it off the front. had a pvc sock and two hose clamps to stop the water pouring in once off

[daddle]

Before removing the bellows jump in and plug up the inlet, whatever it may be, as best you can. A rag should work. Do this after pushing the shaft aft. No need for a haulout.

[noelex 77]

I guess I get too nervous with water spurting into the boat

[Dockhead]

Originally Posted by noelex 77

I guess I get too nervous with water spurting into the boat

Hah, me too!

I come out briefly every two months for a scrub off, anyway. Can it be done in 45 minutes? That's how long I get to do whatever I need to do below the waterline, according to my price plan.

[S/V Pearl]

Dockhead, I know of a case where the PSS shaft seal failed and nearly sunk the boat. The insurance company refused to pay as it was part of the "wear and tear" exclusion. On Pearl I have the entire unit replaced or rebuilt by a reputable boatyard every 5-6 years.

Keith