Cutlass Lube?

[Crazyhorse 47]

Probably been hashed a while ago but has anyone ever run a water feed to the prop tube via the air breather on a PSS seal? We went vesconite last year and were surprised to get a little bit of play and thinking there may not be a enough

water getting past the bearing? Heating up? A 'T' joiner from the hiscock to the PSS? When the engine is running, the path of least resistance would be the skin fitting but it would also draw a small amount of water up the prop shaft too?

[harrytom 642]

The Chatfield dripless has a water connection 6mm and a grease nipple which needs a shot every 100hrs ,I had a T on the water feed to engine,never had a leak and periodically check for heat,never had an issue,What I did like about the chatfield was if a issue developed you could loosen 2 nuts on a flange and install gland packing,had mine 3 yrs never had any trouble,proberly done 300 odd hours.

 

[Crazyhorse 47]

Thanks Harry. Will give it a go as water should equalize in the shaft tube so no need to burp the gland?

[waikiore 398]

The tail on the PSS is for a water feed, not just an air breather, just dont pressurise it too much it needs the water to stay cool and lubricated, this has the added benefit of a positive flow down the stern tube. 

[Crazyhorse 47]

Yep. Rang the supplier who said go for it, connect the PSS feed direct to the raw water supply for the engine via a tap. This we have done! The yard did our propspeed so got a safety pin to clear the groves in our vesconite cutlass so water flows through and there is only ONE!? I thought they needed multiple groves? The old bronze rubber one did. It's a large grove and when I burped the gland last year was able to suck water up. Well, we have already done one summer on this setup and no issues so put the pin up that groove and all good. I am expecting the impeller on the engine will draw most of its water through the hiscock valve / skin fitting and probably a little bit via the PSS seal. There is also a valve on the PSS supply so I can turn that off when burping the gland. Will let you know how it goes......or how it doesnt.

[waikiore 398]

Err I should have made that clear the PSS or Blue Water Seal has to be on the downstream side of your seawater pump not before it,  and only 5/16" or 8mm taken before the water goes into the engine ie cold water.

Yes Vesconite bearings typically for a 1" shaft four water grooves (not on the bottom) and larger bearings six or eight grooves.

[Crazyhorse 47]

Was told as the plumbing is below the water line, whatever the pump draws will mostly come from the raw water skin fitting. If it does draw some up through the prop shaft tube there is nothing to worry about. Running a feed from the pressure side if the impeller pump can over pressure the PSS seal. Water flowing up the stern tube instead of down? Remember, we have had nothing on the feed pipe for over a year since the PSS was installed. 2002 on the previous seal too. The vesconite bearing has only one groove, 1 inch shaft. Probably why there has been a very small amount of wear since it was installed last year. (Pick your engineer's!)

[Steve Pope 243]

I have a bleed from the engine water feed to the exhaust that lubes the bearing that has a small take off from it that dumps into the cockpit, if it is not running it means the pump has failed or has shed a blade or 3.

[Crazyhorse 47]

I have a bleed from the engine water feed to the exhaust that lubes the bearing that has a small take off from it that dumps into the cockpit, if it is not running it means the pump has failed or has shed a blade or 3.

Good idea. Not sure about squirting water into the cockpit, ours is a bit small...wet feet. We launch Wednesday so will see how the mods work. Can't make it any worse as there is no way for air to get into the prop shaft tube if the raw water feed creates a vacuum. Air wouldn't get past the PSS. That would be the only worry I think as any water that gets drained out through the nozzle will simply be drawn up through the cutlass bearing. Geoff at Whangarei Marine Services seems to think it will work fine. We run a cockpit wash off the raw water feed to the engine via a non return valve and a salt water tap to the galley and with the engine running, neither starves the cooling system so lots of water getting in through the strainer. Large diameter tubing. Will let you know how it goes.

[Crazyhorse 47]

So far so good! Engine, prop shaft and seal all very good after 6hrs.

[waikiore 398]

Perhaps this needs repetition: Both the Blue water seal and the PSS seal should be fed from downstream of the raw water pump before it enters the engine if too much pressure use a small inline thumb valve to limit the flow. Anything else is your own call and demonstrably outside what the designers and manufacturers  say.

For both on a yacht engine at 1000 RPM should fill a coffee mug in a minute- not big volume and not high pressure.

I have tested these for many hours and on faster launches and modern yachts you can easily evacuate the stern tube . There is sound engineering and years of testing on the bench and at sea behind these products, why spend the money then ignore the written instructions?

Rant over I must be getting old.