A Leak!

Funny the emotions that play out, even in a relatively benign situation.
We were headed up to the Camano gathering on Pender Island in BC on Saturday. Left Tacoma about 10 and pulled into the marina in Port Townsend about 4 pm. As we're docking, Sara hears water running. Look around and its a pretty good stream (light garden hose?) running out of our boat. Ooops, dat be the bilge pump. Did some investigation and lo and behold, we've got a bunch of water coming through the formerly dripless shaft seal. Enough so it keeps the bilge pump running about 60% of the time.
Check with the haul out guys at Boat Haven marina. Sure, we can call guys in and pull your boat as an emergency, but you still can't get parts etc until Monday. Or, you could leave it in the water, watch the pump, and we'll pull it Monday at about half the price.

So we decided to wait until Monday. We had the lift guys' cell phone numbers and they promised to get us out promptly if things got worse.

Tied up and enjoyed the town for a couple days. On Sunday afternoon, noticed that the water was coming out from the opposite side of the boat. Huh. Only dawned on my in the middle of the night that the switch was caused b a failed bilge pump. water rose over a small bulkhead to the next compartment, where that bilge took over. So NOW I'm concerned. Naturally didn't sleep a wink the rest of that night.

Bright and early Monday boat is out and on the dirt. Pulled the seal loose and slid it forward. Was able to slide the shaft back enough so that the seal could come off without pulling the shaft. The seal was melted into a big blob. Hot enough to mark up the shaft pretty well. Fortunately, Fisheries had a Sure Seal in the right size, which they shipped over to Pt Townsend for free. Back together and in the water by Tuesday afternoon.

Failure was caused by something blocking the water flow into the seal. There is a gravity feed water line coming off the aftercooler that feeds the seal. Once that plugged, the seal just plain melted.

Had zero warning on this. Not a drop of water before we started the trip. On the Camanos that seal is way back in a recess pretty deep in the keep form hull, making it harder as hell to get to.
the new seal has two water inlets, which lessens the liklihood of both being plugged. It also has a spare seal fastened to the shaft in front of the one in use, making a change out pretty painless.

The only think I can think of to try and anticipate
this more is to use an infrared gun to check the temp of the shaft while running.

sorry about the large photo, but its of the seal after removal

That certainly could ruin your day... Glad you got it fixed.

Well saved. Something to be said in favour of the old stuffing box, it usually fails slowly and warns in advance.

I'm glad you caught in time. Finding water flowing into the bilge always makes the heart skip a beat.
Dripless shaft seals are great...until they're not, and it happens fast.

Doing occasional temperature checks on a standard gland packing is adequate, but with a mechanical seal an infrared sensor with an alarm may be worth considering.

Something like this.

or you could pick up the components and build your own for less than $100 if you are into that sort of thing.

" Something to be said in favour of the old stuffing box, it usually fails slowly and warns in advance."


An old style stuffing box with modern packing would be a great upgrade.

I have the same seals (twin engine). User manual calls for testing the water flow regularly. With twins I have some advantage that the water can cross feed ( that extra feed line) but it still is a concern. As you know, the spare seal can be replaced in the water, although it is not for the faint of heart because the water flow during the operation is significant.
Of course this option is only of value if you can get at the seal and it sounds like maybe you cannot. You need to be able to get two hands in there to swap the seal. I had to do some mods to be able to access one of the engines.
You mentioned gravity feed... The user manual calls for a minimum 3 gal/minute, if I recall. Do you get that with gravity feed? I would look over all the plumbing to the seal and make it as fair as possible, and minimize any constrictions that might cause a problem.
I use a heat gun during engine checks but I really like the previous post for a remote temp sensor. A wireless remote would avoid the long wire to the pilot house if I can find such ( a slight creep from the OP?)

Interesting idea, infrared temperature sensors. I could see using a dozen or more all over the ER, tied into the NMEA 2000 backbone.

Meanwhile, I try to remember to do regular engine room checks underway, and shooting various things with the IR thermometer is part of the routine. I'm not sure it would have been possible to spot the OP's failure in time, though.

And obviously you need to solve your bilge pump issues. IMO:

1. Get a quality switch, the Ultra Safety Systems Pumpswitch Senior which includes high water alarm capability.
2. Install back up high capacity high water bilge pump.

Hmmmmm. Think I might add a third bilge pump.

I have investigated a few flooding losses caused by "dripless" shaft seals. My personal boat uses a simple bronze packing gland for this very reason.

I had a stuffing box overheat one time when a small piece of rubber from the impeller on the raw water pump got stuck in the coolant hose running from the engine to the stuffing box. It was jammed up in a small fitting.

The old stuffing boxes with new packing are far better IMO.

"Maintenance Free Dripless Shaft Seals,"...I'll stick with packing every time.

Yep, modern packing is the way to go

More bilge pumps but also bilge alarms.

Just a check on the gravity feed that was mentioned - our water feed for the seals comes from the back of the engine coolant heat exchanger (FL 135s) so it is delivered under pressure to the seal - not gravity. Is that the same coming from an intercooler?

SoWhat said:

Hmmmmm. Think I might add a third bilge pump.

Click to expand...

The AT came with on bilge pump. I now have 4. One in each compartment.

I believe I have 2 or maybe 3 spare dripless shaft seals mounted on the main shaft. It's not worth crawling down, removing all the crap, lifting the floor boards to count the spares. I know they are there because, I put them there. SMILE

A bilge pump that is always running as long as the shaft is turning and doesn't hurt fuel economy until it's needed. Could be a lifesaver in some situations. No affiliation.


Fast Flow Emergency Bilge Pump

Brisyboy said:

Just a check on the gravity feed that was mentioned - our water feed for the seals comes from the back of the engine coolant heat exchanger (FL 135s) so it is delivered under pressure to the seal - not gravity. Is that the same coming from an intercooler?

Click to expand...

Same with our 135's.

Ski in NC said:

I have investigated a few flooding losses caused by "dripless" shaft seals. My personal boat uses a simple bronze packing gland for this very reason.

Click to expand...

I know personally of two boats almost lost by the failure of their "dripless" shaft seals.
Not worth the risk.

A smart looking 2008 trawler just sold fast here. With new Volvo engines, courtesy of a failed shaft seal.

I don't know of any boats that have sunk due to a failed dripless seal. I have "heard" a lot of chatter about severe leaks. After some research, it seems that some or most of those leaks were due to neglect. I have researched them enough to know how they work and how to care for them. I would prefer a traditional style packing/stuffing box or gland. That is what I will install on my boat.

Sheesh, you guys are scaring me. Reading this topic I called to my wife “TAKE THE HELM! (please)”. I then grabbed my temp gun and quickly popped open the ER, donned the ear protection, and knelt down in the ER and shot the shaft seal. The shaft was 80 degrees, the carbon stator was 70 degrees, and the bellows was about 72 degrees. ER temps were about 100 degrees. This was after about 4 hours of running at 1500 rpm.

I had the dripless on my Catalina 36, Catalina 400, and now the North Pacific. I haven’t sunk yet! With this kind of luck I might as well have bought a gasser to go along with my propane stove and single engine. ;-)

Having said that, if I ever did need to replace the seal, I might consider a traditional packing gland with modern packing.

dhays said:

Sheesh, you guys are scaring me. Reading this topic I called to my wife “TAKE THE HELM! (please)”. I then grabbed my temp gun and quickly popped open the ER, donned the ear protection, and knelt down in the ER and shot the shaft seal. The shaft was 80 degrees, the carbon stator was 70 degrees, and the bellows was about 72 degrees. ER temps were about 100 degrees. This was after about 4 hours of running at 1500 rpm.

I had the dripless on my Catalina 36, Catalina 400, and now the North Pacific. I haven’t sunk yet! With this kind of luck I might as well have bought a gasser to go along with my propane stove and single engine. ;-)

Having said that, if I ever did need to replace the seal, I might consider a traditional packing gland with modern packing.

Click to expand...

At those temps,,,,,









:lol:

I have seen a number of failures over the years and in most cases it was either a small section of rubber from an impeller of a section of zincs blocking the water inlet.
On most of my new build projects we use a small pump saver in the cooling water inlet to prevent this problem.
On twin engine boats the preferred systems is to rig the water inlet to both engines giving you a second source of cooling water.
As a matter of tradition I always do engine room checks every hour and check and note the shaft seal temp.

Having had this failure a few years ago I found a bicycle inner tube split down the middle makes a great warp and prevents water intrusion

Just working said:

I have seen a number of failures over the years and in most cases it was either a small section of rubber from an impeller of a section of zincs blocking the water inlet.
On most of my new build projects we use a small pump saver in the cooling water inlet to prevent this problem.
On twin engine boats the preferred systems is to rig the water inlet to both engines giving you a second source of cooling water.
As a matter of tradition I always do engine room checks every hour and check and note the shaft seal temp.

Having had this failure a few years ago I found a bicycle inner tube split down the middle makes a great warp and prevents water intrusion

Click to expand...

We were recently discussing dual-engine water intakes over on PNW Drifter's build thread.


The pics start at post #241 and the conversation picks up shortly after.


http://www.trawlerforum.com/forums/s25/farrell-trawler-rebuild-project-40220-13.html

dhays said:

Sheesh, you guys are scaring me. Reading this topic I called to my wife “TAKE THE HELM! (please)”. I then grabbed my temp gun and quickly popped open the ER, donned the ear protection, and knelt down in the ER and shot the shaft seal. The shaft was 80 degrees, the carbon stator was 70 degrees, and the bellows was about 72 degrees. ER temps were about 100 degrees. This was after about 4 hours of running at 1500 rpm.

I had the dripless on my Catalina 36, Catalina 400, and now the North Pacific. I haven’t sunk yet! With this kind of luck I might as well have bought a gasser to go along with my propane stove and single engine. ;-)

Having said that, if I ever did need to replace the seal, I might consider a traditional packing gland with modern packing.

Click to expand...

Dave:

No panic, please.

The first of the boats I know personally is a GB 42. Hit a log, the impact caused the dripless to be shifted on the shaft, so that after the hit, there was a gap between the surfaces that are supposed to be together, letting in a constant stream of water that overwhelmed the pumps in a short while. Sinking was averted, but it was a very close call.

The second is a C&C 36(or 35?). a poorly loaded locker above the seal allowed something to get wrapped around the turning shaft, destroying the bellows, and a steady stream of water far beyond the capacity of the pumps entered the boat. Only good luck and the presence of a diver prevented sinking.

One of my sons has a pair of dripless in his Monaro 27. He knows the risk and is vigilant.
My other son has a much older boat with an ordinary stuffing box with the modern coated packing. He is not tempted to change.
I have a pair of old style stuffing boxes, modern packing. Simple, reliable.

In choosing a boat, you need to be aware of the risk, decide whether you can be vigilant enough to minimize the risk. Make your choice.

Could part of the seal issue be not replacing seals as the mfr recommends. The can`t last forever. Neither does packing, but at least you get a watery warning as they wear, to nip up or repack.

BruceK said:

Could part of the seal issue be not replacing seals as the mfr recommends. The can`t last forever. Neither does packing, but at least you get a watery warning as they wear, to nip up or repack.

Click to expand...

If I recall, for the type of PSS that I have the recommendation is replace the bellows every 6 years. When you replace the bellows you also need to replace the seals on the stainless rotor, not because they wear during use, but you have to remove the rotor to replace the bellows and that process can cause wear on the seals. So while not essential, I don’t see any reason to NOT replace the seals at the time. I think the entire kit from PSS to replace bellows, seals, set screws and clamps is about $100.

The issue is that the bellows will wear with age, heat, exposure to chemicals or battery acid vapors. I have no idea where PYI gets their 6 year recommendation, my guess it is from the loss prevention dept of their insurance carrier. The PSS on my Catalina 400 was installed in 2006 when the boat was new. It had not been replaced by the time I sold the boat on the last day of 2015. My current boat was built in 2010. It still has the original PSS seal and bellows.

I’m not worried about it, however... At some point I will need to have the cutlass bearings looked at/replaced and would have the PSS bellows replaced at that time.

Couldn't sell me a seal like that, wouldn't take one as a gift either.