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Old 05-13-2020, 08:39 PM   #41
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I've little experience with modern packing materials, I gave up on the old packing glands with the advent of dripless seals. It seams like they would have the same issue with heat and needing lubrication as a dripless seal? On my boat, there are two cutlass bearings, separated by about 4'. Both are in the keel. Duramax requires 2 gallons/minute water minimum through the bearings. This can only occur with a pressure water feed from somewhere - it isn't going to backup from the aft one to the forward one on a lark. So how and why in this situation would a packing gland work better than a lip seal? Why are they really very different? Don't both press a flexible material against the shaft to seal the water out?
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Old 05-14-2020, 02:10 AM   #42
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For my upper bearing my boat has a clamshell that feeds water into the chamber ahead of the bearing. Seems like a better idea than trying to use the excess from a packing gland.

My prior two boats I had early PSS seals and liked them. For the last 14 years Ive run gore packing in a traditional gland. Dripless seals dont make sense for me anymore, now that the gore packing has become so well proven and comes without the added failure points of the dripless.
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Old 05-14-2020, 06:16 AM   #43
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"I concur...how many feet (yards) of packing could I buy for the price of two dripless seals?"

Not that many,

The Goretex or Duramax are fairly expensive , but cheap as insurance against sinking.
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Old 05-14-2020, 11:28 AM   #44
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A while ago I had another boat with a similar shaft seal but in this one, instead of the small pipe being connected to the engine intake, it was connected to an underwater through hull seacock. Boat cruised at 22knt, had it for 10y with no issues
Happy to hear that, because it's exactly the same setup that I've got in my current boat, which I've only had for two seasons, but is by now 16yo and never had a problem with her Fluiten seals.

The advantage which I see in dedicated seacocks, on top of not "stealing" water from the main circuit (which is also true in your setup of course, as opposed to more typical solutions where the pickup is downstream of the raw water pump), is that the dynamic pressure on the pickup point increases with speed, while I suspect that in your setup it's the opposite, at least to some extent.

Then again, if your system worked so far without any trouble, as the old saying goes, if it ain't broke...
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Old 05-14-2020, 11:31 AM   #45
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No Xantex horror stories on this boat.
Therein lies your problem. Magnum all the way when it comes to inverters!!!
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Old 05-14-2020, 12:20 PM   #46
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For my upper bearing my boat has a clamshell that feeds water into the chamber ahead of the bearing.
The chamber ahead of my forward bearing is the bilge, so not possible.

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Therein lies your problem. Magnum all the way when it comes to inverters!!!
There are Magnum inverter horror stories aplenty. I'm quite sorry I bought the one in my RV.
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Old 05-14-2020, 12:37 PM   #47
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There are Magnum inverter horror stories aplenty. I'm quite sorry I bought the one in my RV.
Ok they all suck...you happy? Magnum is the best out there...IMO and experience. None are perfect.
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Old 05-14-2020, 02:08 PM   #48
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My Taiwan built trawler has a sump in the forward part of the engine room where all bilge liquids collect, including shower water, thence pumped overboard, thus, we always have a dry bilge.
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Old 05-18-2020, 02:22 PM   #49
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Far better off with a temp sensor/alarm on the seal. Tides sells a kit.
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Old 05-19-2020, 12:42 AM   #50
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My boat is keeled cooled and dry exhaust, so I don't have any sea water being pumped by the engine. I use an electric pump that supplies Sea water to the two shaft seals, and the refrigerator/freezer condensers, whenever any of them is switched on. I went through a period of pumps that were overheating and tripping off unexpectedly, and I would loose cooling to the dripless seals. Despite the boat operating at slow speeds that the dripless seal literature implied I shouldn't even need cooling, fairly quickly they would start making a loud groaning sound when underway. At this point the outside of the seals was warm to the touch, but not hot. I would shut down the engines and mess with the pump till I got it running again, or changed out for a spare, which I got very fast at. When I started back up with cooling, the seals would leak a tiny bit for the next few hours. Just enough to fling around a fine mist of salt water all over everything. The noise was very obvious long before they catastrophically burned up. I think I finally got my problems solved by switching to a magnetically coupled centrifugal pump that is designed for continuous duty. Just in case, the old pump is still installed as a backup, that can be quickly put in service by open/closing a couple valves, and switching the Deutsch connector on the power feeds.

Edit- My boat also has temperature alarms that sense on the aluminum shaft tubes just behind the seals. Never in these in multiple incidences did the temperature get anywhere near high enough to trip the alarms. I think at least in the beginning the problem starts right at the face of the carbon and stainless surfaces. When they were dripping afterwards I pulled them back and felt the surfaces with my finger and they felt completely smooth. Whatever scarring they had must have been very small. They always seem to fix themselves after a few hours. It really freaked me out the first couple times it happened.
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Old 05-19-2020, 08:12 AM   #51
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snip.... Despite the boat operating at slow speeds that the dripless seal literature implied I shouldn't even need cooling, fairly quickly they would start making a loud groaning sound when underway. At this point the outside of the seals was warm to the touch, but not hot.....
If you are using PSS seals then my read of the installation instructions say if you're not supplying water to the seal then the water line from the seal needs to be vented above the boat's waterline. With a failed pump in the water line yours wasn't vented but blocked.

The failure I experienced, which started this thread, was a blockage in the PO installed flow meter. So I had similar conditions to yours, no flow, no venting. The seal got uncomfortably hot, probably hot enough to set off an alarm if installed. Alarms will be installed because the seals and shaft logs are aft of the engine room under the aft cabin decking. To access the port seal for inspection I need to move furniture and pull up carpet. The starboard seal is under the head decking, easy to get to.
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Old 05-27-2020, 10:02 PM   #52
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Look at Borel Manufacturing. I have their alarms on the exhaust, high water and water in fuel. Easy install and draws no power unless there is an alarm. No affiliation just a very satisfied customer.
Question regarding the Borel or similar alarms:
Each of my engines has 2 exhaust elbows. Do you just put an alarm band on one of the 2 exhausts of each engine assuming that failure would likely be upstream and affect both?
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Old 05-27-2020, 10:58 PM   #53
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Question regarding the Borel or similar alarms:
Each of my engines has 2 exhaust elbows. Do you just put an alarm band on one of the 2 exhausts of each engine assuming that failure would likely be upstream and affect both?
Since exhaust elbows can also become clogged, it is best to have them both monitored.
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Old 05-28-2020, 11:25 PM   #54
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I understand how why the dripless seals solved a problem decades ago , but wonder why folks put up with the risk and maint required today?

A modern packing in an ancient designed stuffing box can frequently go years with out requiring an adjustment.

With no danger from sinking from a not replaced on sked rubber bellows or tiny plastic tubing.

Why bother when better is OTS. ?
I'm not sure what risk and maintenance you are talking about. I've had both over my lifetime, and they both work. But, it is a stuffing box that needs maintenance with periodic tightening. A shaft seal basically needs no maintenance, but you may change them out at factory prescribed intervals if desired. I've known many folks that didn't even do that and went on longer.
The newer PYI seals have even longer replacement intervals. Bilges stay dry. I never even thought to monitor the water flow. I'll add that to my list. I don't think I'll go for more electronics/monitoring, other than hand touch and maybe IR gun.
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Old 05-28-2020, 11:31 PM   #55
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People. They both work if installed correctly, and inspected from time to time. I think this is being over-argued.
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