Dripless Shaft Seal Cooling water

[Blitz]

Long story but my boat yard is recommending the replacement of my traditional stuffing box with a dripless as part of the rebuild of my shaft log. I don't have an issue with a traditional stuffing box or the very small amount of water it drips with GFO fiber packing. Also I will never have a perfectly dry bilge since I have a keel stepped mast.

The yard is recommending the Tides Marine Sureseal. I was wondering if anyone here uses this brand of dripless Shaft Seal. with a Yanmar. My worry is that it appears this type of shaft seal seams to require cooling water. That seams like it would be a draw on the exhaust cooling and more importantly what happens when the engine isn't running and the prop is free spinning while I'm sailing??

The Tides Marine shaft seal seams to be used on many power boats, and when used with a dual engine set up in which requires cooling water to the opposite engine when only one engine is running to prevent overheating. Also, youTube showed leakage when engine was shaking even slightly. they also recommend a flawless shaft.

My engine is a raw water cooled Yanmar 3GMD which recommends allowing the prop to spin while sailing.

It seems the Glide shaft seal is similar to the Tides Marine shaft seal.

Any thoughts or experience on this?

 

[Tally Ho]

No experience with the Tides Marine product. It appears to be a lip seal, in a holder, so it is replaceable. It seems very similar to the Johnson version that @RSHunter27 installed…

Measurements of the Cutlass Bearing?

A new shaft may be the way to go…you don’t want to doing this job again :( If the prop was colored by the acid, and is bronze still shiny with a little polishing, maybe it is OK. Other than the colors, it looks ok. No corroded edges. Greg

forums.sailboatowners.com

He made some comment about being unsure he would use it again, but I don’t know why.

For my money, the Volvo Penta rubber stuffing box, which also uses a lip seal, is about as cheap and simple as you can ask for. It requires no water for cooling, just a “burp” once in a while to get any air out…I usually do it when I open the engine water intake through hull. Most people only do it when they launch.

It seems very robust, and very dripless. I am on my second or third season with it…and I am very happy with it.

Greg

 

[Ralph Johnstone]

If @Tally Ho recommends the Volvo Penta shaft seal, that's about as factual a report as you're going to get on shaft seals.

Me, I'll stick with my primordial stuffing box as I've got it set to run dry. The shaft surface has a mirror like polish under the packing.

 

[RSHunter27]

No experience with the Tides Marine product. It appears to be a lip seal, in a holder, so it is replaceable. It seems very similar to the Johnson version that @RSHunter27 installed…

Measurements of the Cutlass Bearing?

A new shaft may be the way to go…you don’t want to doing this job again :( If the prop was colored by the acid, and is bronze still shiny with a little polishing, maybe it is OK. Other than the colors, it looks ok. No corroded edges. Greg

forums.sailboatowners.com

He made some comment about being unsure he would use it again, but I don’t know why.

For my money, the Volvo Penta rubber stuffing box, which also uses a lip seal, is about as cheap and simple as you can ask for. It requires no water for cooling, just a “burp” once in a while to get any air out…I usually do it when I open the engine water intake through hull. Most people only do it when they launch.

It seems very robust, and very dripless. I am on my second or third season with it…and I am very happy with it.

Greg

He made some comment about being unsure he would use it again, but I don’t know why.
I don't know that it was me that said that I really haven't had the opportunity to see it in action. Last night I put my engine back in the engine compartment, today I connected to the shaft and locked everything down, hooked up the exhaust and water and set up the basic electricity to the starter. Tomorrow I will complete the electrical run through my checklist and start it up. I was unable to include all of my improvements that I intended, as in one week I will be without power and such in this Lake as it is way too low and they will be moving us out into the middle where I will have no power. I've made a reservation for a slip in Kemah Texas which is just inside clear Lake on the entrance to the Gulf. The challenge will be getting my boat hauled out of this Lake as there isn't enough water level to haul out at most facilities. I have heard there is one left. And I don't know how long that will last. Anyway I did remove my prop and clean up the shaft and Cutlass. Don't know that I want to do that again while in the water. In any event I will be posting my current events back on my thread.

 

[RSHunter27]

If @Tally Ho recommends the Volvo Penta shaft seal, that's about as factual a report as you're going to get on shaft seals.

Me, I'll stick with my primordial stuffing box as I've got it set to run dry. The shaft surface has a mirror like polish under the packing.

RALPH YOU'RE SUCH A TRADITIONALIST! I DON'T KNOW THAT THERE IS ANYTHING WRONG WITH THAT.

 

[Ralph Johnstone]

RALPH YOU'RE SUCH A TRADITIONALIST!

"Traditionalist humph".

You start making fun of my spats :

.............................. and there's going to be words.

 

[jssailem]

The shaft seal be it traditional or dripless has nothing to do with your engine. It is all about the space you have between the shaft log and the transmission coupling. There are several dripless brand designs. Space to access the shaft seal is a boat engineered specific. Different brands seal the water out in different methods.

With regards to the cooling hose, the volume of water consumed by a 1/4 inch hose running down from the heat exchanger (like I have) or a T tap like is often added to the water line of the exhaust is of no concern to the exhaust heat dispersion by the volume of water pushed through the exhaust elbow and out your exhaust system.

This water in the shaft log helps to cool the seal parts by constant flow. Water forced into the shaft log is necessary for power boats due to the high speed rotation of their shafts. Cavitation in the shaft log can create air bubbles. Not the issue on a sail boat. Some shaft seal manufacturers suggest you just fix the hose high in the boat to provide a way for any air in the shaft log/shaft seal to escape. I have the theory that water in the shaft log may help to remove sand that finds its way up the shaft log when driving the boat in reverse.

There is a concern that I stumbled upon with the shaft log hose. My shaft seal hose connection goes up to the heat exchanger. During the repair of a failed raw water pump, my mechanic removed the pump. He set the pump hose, to the exhaust, aside while we worked on the pump. Parts took a week to acquire. When I closed up the boat all was dry. Some how the raw water pump hose moved. It slipped below the level of the heat exchanger. This created an opportunity for a siphon to develop. Water came up from the shaft seal. It flowed into the HE through the engine and out the hose into the bilge. The result. My boat tried to become a submarine. I got a call from a slip neighbor “I think your boat is sinking!” Sure enough. Phone calls to the marina. High speed run 250 miles to the boat. Marina crew pumps water out of the boat. Mechanic called to assess and resolve the problem. Many dollars later. More work projects.

Caution advised when removing a hose. Know what is connected and act accordingly.

I installed the PYI PSS Dripless shaft seal. So far it has worked as advertised. I’ll post info regarding performance once I have some hours on the unit.

 

[BigEasy]

For my money, the Volvo Penta rubber stuffing box, which also uses a lip seal, is about as cheap and simple as you can ask for. It requires no water for cooling, I am on my second or third season with it

16 years with a Volvo shaft seal with no problems. Inexpensive & robust. Doesn’t leak a drop & bilge remains bone dry. I lubricate it annually with Volvo grease. I do have dedicated raw water flowing into the shaft log, just aft of the seal to lubricate the seal & internal cutlass bearing. Very pleased with this seal; no moving parts like the PSS seal. Cost is a bit over $100.

 

[Hayden Watson]

I installed a Lasdrop lip seal and have been very happy with it. On a sailboat, the nipple does not need to be connected to a water source, It is just a vent with an open-ended hose that is secured to a point well above the waterline.
DrySeal Lip Seal | lasdrop.com

 

[kappykaplan]

I installed the PYI PSS Dripless shaft seal.

That's what I have - replaced with a new one at the last winter refit. Bilge has stayed much drier this year. Previous unit was not doing well after 15 seasons.

 

[Blitz]

With regards to the cooling hose, the volume of water consumed by a 1/4 inch hose running down from the heat exchanger (like I have) or a T tap like is often added to the water line of the exhaust is of no concern to the exhaust heat dispersion by the volume of water pushed through the exhaust elbow and out your exhaust system.

My worries is that I have a theory in that a engine manufacturer designs their raw water cooling circuit to properly cool their engine design, and assuming the exhaust; but that is normally the boat manufacturers design which should be more or less the common industry practice. When items are added to draw cooling water off of that design for the exhaust, I think we may be playing with fire (may be literally) unless the entire design of the system is reviewed.

This water in the shaft log helps to cool the seal parts by constant flow. Water forced into the shaft log is necessary for power boats due to the high speed rotation of their shafts. Cavitation in the shaft log can create air bubbles. Not the issue on a sail boat. Some shaft seal manufacturers suggest you just fix the hose high in the boat to provide a way for any air in the shaft log/shaft seal to escape. I have the theory that water in the shaft log may help to remove sand that finds its way up the shaft log when driving the boat in reverse.

I sent a question into Tides Marine to clarify if the cooling water is really needed for sailboats, and if so what about when the prop is spinning with no engine cooling water when sailing. I like your theory though.

Caution advised when removing a hose. Know what is connected and act accordingly.

Good Advice! Thanks

 

[dlochner]

There are a couple of ways to get cooling water into the shaft seal, either naturally with a vent in the seal or under pressure with a tap from some water source.

PYI uses a passive vent in the seal. There is a hose that extends from the seal to above the water line. In the old sailboat versions of the PYI it was necessary to burp the seal to allow water to flow all the way into the shaft log. The vented versions do not need to be burped.

Sailboat engines run at a lower RPMs than do diesels in power boats or gas engines in power boats. Because they run at lower speeds less heat develops which leads to lower cooling needs. The passive venting works for diesels in sailboats.

The big concern with dripless systems is the integrity of the boot. PYI recommends changing it out every 6 or 7 years. If the boot fails there will be a tremendous influx of water. Traditional stuffing boxes that are self-aligning, i.e., are connected to the shaft log by a piece of hose would seem to be subject to this problem too.

I installed a PYI seal on my old Sabre 30 because the stuffing box was in a very difficult place to access and adjust. A trip there every 6 or 7 years seem preferable to an annual or more frequent visit.

 

[Blitz]

If @Tally Ho recommends the Volvo Penta shaft seal, that's about as factual a report as you're going to get on shaft seals.

Yep, The Volvo Penta Shaft Seal almost looks too good to be true!

No cooling water necessary. I think I read somewhere the lifespan is about five years.

I see a lot of examples on YouTube of these Volo Penta dripless seals leaking as well. Our little Yanmars wiggle a bit, even with like new engine mounts so alignment seems very crucial to their sucess but I guess that is with any seal. Also, who knows if they are greasing them annually or burping them.

 

[RSHunter27]

I installed a pillow block bearing in front of my Johnson. Along with a flexible shaft coupler, I'm expecting to lose that movement in the vertical and horizontal while maintaining stable axial movement. I have reinstalled my motor and will be firing her up by the end of the day. I'll keep you all posted on the outcome and the merits of this process. Hopefully it's not just a "shaft dream".

 

[Davidasailor26]

Yep, The Volvo Penta Shaft Seal almost looks too good to be true!

No cooling water necessary. I think I read somewhere the lifespan is about five years.

I see a lot of examples on YouTube of these Volo Penta dripless seals leaking as well. Our little Yanmars wiggle a bit, even with like new engine mounts so alignment seems very crucial to their sucess but I guess that is with any seal. Also, who knows if they are greasing them annually or burping them.

I am a fan of ours too. 9 years / 650 engine hours and no drips, but it probably is about due for replacement. Ours does have a water injection line off the back of the 3YM30 heat exchanger. We had a fixed prop for the first 3 seasons and never had any problems from the freewheeling prop while sailing. After that we switched to a folding prop.

 

[Justin_NSA]

This has been pretty well covered already. In a nutshell, forced water is needed for powerboats to provide cooling due to cavitation or starving at the seal. Sailboats travel much slower so they just need to be vented to break the siphon and prevent cavitation

 

[Blitz]

FYI - For the Volvo Dripless Seal I noticed many of the Beneteu have a cooling port directly into their shaft log tube.

 

[Blitz]

Interesting, I spoke to Tides Marine about their Sure Seal; my concern over cooling water, and my Yanmar 3GMD. Their recommendation was not to hook it to the engine, but to hook it to the engine's thru hull fitting. This will provide enough flow, especially in a sailboat whether the engine was running or not. They also recommended duel injection fittings so that one would be used as a vent. They recommended a special order double ribbed hose to allow for the increased movement on a Yanmar 3 cylinder like mine and if I have the space to put a spare seal carrier kit on the shaft to allow for easy seal replacement in the future. Basically as soon as I said I had a 3 cylinder Yanmar he knew my concerns. So if nothing else they do have good technical service and I highly recommend talking to them before ordering anything.

 

[Ralph Johnstone]

D. Their recommendation was not to hook it to the engine, but to hook it to the engine's thru hull fitting.

If they are telling you the thru-hull that supplies sea water to the engine, bad idea. The raw water pump pulls from this hose and the hose is under negative pressure before the pump. I would think this would melt your seal.

Perhaps what they meant was the raw water discharge from your heat exchanger. This hose contains sea water under pressure and has no influence on the amount of water going through your system if some of it is diverted.

 

[RSHunter27]

If they are telling you the thru-hull that supplies sea water to the engine, bad idea. The raw water pump pulls from this hose and the hose is under negative pressure before the pump. I would think this would melt your seal.

Perhaps what they meant was the raw water discharge from your heat exchanger. This hose contains sea water under pressure and has no influence on the amount of water going through your system if some of it is diverted.

What about using the raw water intake for the head?