[C320-list] Shaft zinc?

[Rick]

Daryl,
 If I am not mistaken, stray current in your marina may also impact your hull's exposure of galvanic corrosion that may even effect your heat exchanger where there may be another anode on some engines such as my  Westerbeke.  Since I am also sailing in freshwater I use a magnesium anode from WestMarine that is more sensitive to stray currents than other metals one could use in freshwater. I located the collar anode ahead of the strut about same as the distance as between the packing nut and shaft coupler so in the event the shaft ever departed from the coupler, the shaft will not slide past the GFO packing with making a bad situation worse.  Prop shafts are interference fitted into the coupler plus driven tighter with a slotted key, but even then I learned from a marina technician that a sudden and strong reverse thrust could back-out a shaft from the coupler if there is an installation fit issue or if the coupler set screws are not adequately secured. Hence, a second reason to have a collar anode on your prop shaft.
Rick 
95' 320 Hull #277


-----Original Message-----
From: C320-list [mailto:c320-list-bounces at lists.catalina320.com] On Behalf Of Daryl Hunt
Sent: Tuesday, April 12, 2016 2:01 PM
To: C320-List at Catalina320.com
Subject: [C320-list] Shaft zinc?

I just noticed that Believe doesn't have a sacrificial zinc on the prop shaft.  It does have a 30 amp Zinc Saver II galvanic isolator installed but I assume that applies to shore-power AC.  This is my first spring commissioning of the boat.  I've never had a boat that didn't use a sacrificial zinc between the strut and the hull.
-- 

/Fair winds,/

/Daryl Hunt
s/v Believe, C320 #660
Rochester, NY - Lake Ontario/


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