Dripless shaft seal.

[irwinsailor]

I installed a PYI shaft seal 5 years ago and I now understand that it need to be serviced with a new bellows etc. My question is, is a dripless seal a good choice for a boat that will be used is blue water? Getting to that shaft seal can not be done quickly on our boat.

[RaptorDance]

We are a blue water cruising boat.

We have a 2 Shaft Seals - one on the shaft and one on the rudder post (you don't have to "burp" that one).

According to the research I've done, the recommendation to replace the bellows every 5 years is based on "liability protection" (note- I'm not a lawyer) and not actual need.

According to the best info I've got: If you inspect the bellows and it's in good condition, flexibility, etc. You don't need to replace it that often - UNLESS you have one of those Ozone generators (which you should get rid of ASAP). The Ozone eats rubber and a lot of other materials and you may need to replace them MORE often.

I don't know what the actual service life is but it's well over 10 years near as I can tell.

Regards,
Bill

[irwinsailor]

Does Valiant install dripless seals on their boats when new?

[David M]

I had a dripless seal on mine for over ten years...it worked fabulous. On propeller shafts you need to send forced seawater into it from your raw water cooling system in order to keep the bubbles out and to keep the water oxygenated for stainless steel corrosion reasons.

[S/V Illusion]

Gunner
They are great and require generally less service than their traditional counterpart, however, when they fail, they fail catastrophically and there are many examples I've seem and more I've heard about. If you choose to keep it, it makers no sense given the trivial cost to not follow the recommended maintenance and replacement schedule every 5 years regardless of where you are. Obviously, a spare isn't that cumbersome to carry aboard but replacement in a confined space can be a reason in itself to remove it before you go.

[cooper]

...I have installed one on my new boat, but have since wondered "What happens if I want to take the gearbox off the engine, or do any work invoving lifting the engine, while the boat is in the water ? Unlike a stuffing box where you can slide the shaft out a bit, once the shaft is free floating then it is only the shaft weight compressing the bellows. " I designed my whole engine setup for easy maintenance access and removal if nessesary and it now looks like i have $@^$%# up

[delmarrey]

There are soooo many variables involved in the decision of which one to use.

If it's difficult to get to, that could change my mind. But a wick packing still has to be adjusted once in a while.

As for replacement, an inspection of the rubber and spring tension should suffice, given ones personal skill level.

If either one fails one still has to shove rags in the stern tube to stop the water flow for repairs.

The problem with a stuffing box is it can wear a grove in the shaft without notice. Until that next haulout, in which one may or may not pull the shaft for inspection you'll never know. And a shaft with a substantial wear can not be pushed back either, while in the water.

I prefer the PSS. A new shaft cost much more then a new PSS, unless the boat never travels.

[delmarrey]

Originally Posted by cooper

I designed my whole engine setup for easy maintenance access and removal if nessesary and it now looks like i have $@^$%# up

All you have to do is clean and soap up the shaft. Loosen the set screw, slide the collar back enough to file off the burr so it doesn't cut the o-ring. Then slide the shaft back. Then tighten the set screw and shove something against the end of the shaft to keep it snug against the seal. Just that EZ!

Or better yet, dive under and tightly stuff rags in the stern tube. That acts just like a stuffing box. I here the water is warn down in OZ.

[cooper]

..Measured the water tempreture in the lakes a week back , 21 degrees C at the surface !! Needless to say i didnt bother with the wetsuit. At other times of the year, i have seen "indestructable" kids bounce out a sort of bluey white colour after a few seconds exclaiming that they no longer felt like a swim. I guess your right there must be a way to seal the shaft up. Being a steel boat i always aimed to make it perfectly dry inside. Not long now till I splash her. I just bolted up the rudder and shafts.

[senormechanico]

On my previous boat I had a PSS shaft seal, one of the old originals. It lasted ten years and when it finally started to go it only leaked when we had to motor at a cruising speed of 6 knots. When we realized what was happening (bilge pump alarm sounded whenever the pump ran) we backed off the throttle to 5 knots and it didn't leak a drop! It was one of the original designs which had some sort of fiberglass? weave over the rubber.

I replaced the bellows while we were in the water, no big deal. We sold the boat years later and the replacement was working just fine.

Our current boat has a dripless seal (I don't know what brand but it isn't as good)

It leaks a little, but if it ever really packs it in, I'm buying another PSS.

Steve B.

[RaptorDance]

Gunner - Yes, Valiant installs Shaft Seals as standard on all new Valiants.

[David M]

Originally Posted by cooper

...I have installed one on my new boat, but have since wondered "What happens if I want to take the gearbox off the engine, or do any work invoving lifting the engine, while the boat is in the water ? Unlike a stuffing box where you can slide the shaft out a bit, once the shaft is free floating then it is only the shaft weight compressing the bellows. " I designed my whole engine setup for easy maintenance access and removal if nessesary and it now looks like i have $@^$%# up

You unbolt the coupling between the tranny and the shaft...no problems. If there is weight on it then someone did a lousy job of aligning the engine.

[irwinsailor]

So a maintained dripless seal is safe for ocean passages?

[RaptorDance]

Absolutely! A properly maintained dripless seal is safe for a blue water passage.

Valiant uses them on all their boats.

I heard a quote yesterday that I like - (of course since we agree with it!) - attributed to someone with multiple circumnavigations to their credit.

"If your going blue water cruising on a boat other than a Valiant, you better have a darn good reason!"

Regards,
Bill

[Stranded Mariner]

I am planning to install a dripless seal on my new boat. Any brand names you could recommend? Thanks