Dripless shaft coolant hose vs Fresh water flush

[eandmstern]

Hello Members,

Question: Can the coolant hose for a PSS dripless shaft partially defeat a fresh water flush system?

Details: 16 months and 110 engine hours ago, installed a new gear oil cooler with two 3/8 zincs. It also has a barbed connection to the PSS dripless shaft cooling hose. 14 months and 100 engine hours ago, I installed the SBMAR fresh water flush kit on my Cummins 5.9 6BTA JWAC and use it religiously! The dripless shaft seal cooling hose never goes above waterline, so it always has positive water pressure to the gear oil cooler (which is also below the water line)

I always close the raw water seacock after the flushing procedure. I’m wondering if the freshwater in the system mixes with seawater due to the positive pressure from the the dripless shaft seal hose, effectively getting saltwater into my system. Why am I asking? Because the gear oil cooler zincs were completely wasted after the 16 months and I didn’t expect that after installing the fresh water flush. Even with pressure equilibrium, does saltwater mix with freshwater in that scenario?

Interestingly, my heat exchanger must be above the waterline since it is always empty when I check the heat exchanger zinc which is in great condition- very little wear.

If you’re with me this far, Does it make sense to route the dripless shaft cooling hose above the water line and then back down to the gear oil cooler? can this be done? I can and will consult with PYI, Inc. too. Just trying to guarantee fresh water is in the system.

Any thoughts?

By the way, I have great water pressure at my boat feeding into the freshwater flush Tee, and while I do keep my raw water seacock open during flush I believe it is mostly freshwater feeding it.

Mike

Ps. Yes, I will check zincs and replace more frequently regardless!

Topic

[eandmstern]

Hello Tony,

Thanks for your attention to my question.
Attached is the information you suggested I provide (diagram and photos).

Boat: 2005 Nordic Tugs 32
Engine: 5.96BTA 270 HP JWAC
Gear: TwinDisc 5050SC
Gear Oil Cooler: From SBMAR, with twin zincs and port for dripless shaft cooling on downstream side.
Fresh-water flush: I keep the seacock open, and prior to starting engine, I connect a dockside hose with very good pressure (not measured) and turn it on prior to starting engine. After flushing for 5-minutes, I shutdown engine, close thru-hull seacock, and then close the fresh-water valve.

-Mike

[Tony Athens]

Lot’s left out here to answer this accurately.

Are you flushing with the seacock open or closed? If open, I realy doubt you are 100% fresh in the engine when you shut down.What exact engine?

What comes afer the exhaust mixer all the way to the exahust outlet? Can you supply a skecth with elevation to the LWL

Where is the LWL in rlation to the gear cooler?

Post some good pics showing the entire engine

Best Locations to get Water Flow for Shaft Packings

[Author]

Replies