Dripless seal

[dmksails]

I have some type of dripless seal on my prop shaft. Where is the black rubber hose suppose to go? Right now it's running up the inside of the locker wall with it's end being about 3 feet above the shaft. Should this go into the bilge?

[wingless]

That small black hose is supposed to connect to the engine's pressurized raw water system, providing cooling / lubricating water flow to the dripless seal.

[meridian28]

That’s a PSS shaft seal. If you run less than 12 mph it doesn’t need to be water cooled. It’s sound like it is set up as it should be. The hose just had to be higher than the water line otherwise you would get backflow.

[rbk]

What Terry said or you can run it into an overboard drain for the rare occasion water comes out of it. I 'T' ours into a locker drain.

[Sailmonkey]

It’s just a vent, so run up high is ok

Here’s all you need to know

https://www.shaftseal.com/

[Jim Cate]

Originally Posted by meridian28

That’s a PSS shaft seal. If you run less than 12 mph it doesn’t need to be water cooled. It’s sound like it is set up as it should be. The hose just had to be higher than the water line otherwise you would get backflow.

The hose is a vent which bleeds off any air which gets into the seal area. Just be sure that the end stays above the water line even when at big heel angles and avoid loops.

Jim

[GILow]

Originally Posted by dmksails

I have some type of dripless seal on my prop shaft. Where is the black rubber hose suppose to go? Right now it's running up the inside of the locker wall with it's end being about 3 feet above the shaft. Should this go into the bilge?

As noted by others, that sounds like it is a correctly installed PSS seal. No need for the engine raw water feed at our sailing boat speeds.

But I would add, see if you can find out the age of the seal. Depending on when it was made they recommend replacement every ten years from memory. That one looks in pretty good condition but you should plan for its replacement.

[coopec43]

Originally Posted by wingless

That small black hose is supposed to connect to the engine's pressurized raw water system, providing cooling / lubricating water flow to the dripless seal.

I agree. I have a Tides Shaft Seal which requires raw water from the engine to provide cooling cooling system and lubrication. But there are other types of "dripless seals"
https://www.oceantimemarine.com/need...s-shaft-seals/

[coopec43]

Originally Posted by Sailmonkey

It’s just a vent, so run up high is ok

Here’s all you need to know

https://www.shaftseal.com/

That would be right if it was a PSS shaft seal.


There are a number of different types of dripless seals though and they work on different principles.

[s/v Jedi]

Originally Posted by coopec43

Not really!!


There are a number of different types of dripless seals and they work on different principles.

Yes really, SailMonkey has it right: it is a PSS and it is just a vent.

I used a plastic 1/2” thru-hull fitting to go out into the cockpit so hat any water coming up just spills in the cockpit but it never does.

When you don’t have this hose, you need to burp the seal after launching. Hose is much better

[coopec43]

[QUOTE=s/v Jedi;2941829]Yes really, SailMonkey has it right: it is a PSS and it is just a vent. UNQUOTE




It's not relevant in this case but I know I read somewhere that over a certain speed (10knts?) the manufacturers of PSS recommend pressurizing the seal.

[s/v Jedi]

[QUOTE=coopec43;2941868]

Originally Posted by s/v Jedi

Yes really, SailMonkey has it right: it is a PSS and it is just a vent. UNQUOTE




It's not relevant in this case but I know I read somewhere that over a certain speed (10knts?) the manufacturers of PSS recommend pressurizing the seal.

That is correct. For simplicity we only posted about the setup for the OP’s case.

[Sailmonkey]

Originally Posted by coopec43

That would be right if it was a PSS shaft seal.


There are a number of different types of dripless seals though and they work on different principles.

But it is a PSS seal.....the link I provided has the instructions for venting or feeding raw water, dependent on boat speed.

I put a PSS on our boat 10+ years ago and plumbed it to raw water to keep the deadwood and cutlass flushed clean in our high viscosity home waters, but this wasn’t strictly required based on our maximum speed under power.

[a64pilot]

If you look up PSS installation instructions you’ll see that a boat that has the cutlass bearing in the shaft log has to have water plumbed to the seal regardless of its speed.
I think this is overlooked by many as most of our boats have the Cutlass in the shaft log.

[s/v Jedi]

Originally Posted by a64pilot

If you look up PSS installation instructions you’ll see that a boat that has the cutlass bearing in the shaft log has to have water plumbed to the seal regardless of its speed.
I think this is overlooked by many as most of our boats have the Cutlass in the shaft log.

Hmmm the cutlass bearings that I know will allow water to pass through... are there types that don’t?