Prop Zinc Is Gone and Now I Have White Spots on the Prop

[foggysail]

Originally Posted by swagman

I know it does not seem right, but carbon is a metal.

'A metal is a chemical element that is a good conductor of both electricity and heat and forms cations and ionic bonds with non-metals. In chemistry, a metal (Ancient Greek métallon, μέταλλον) is an element, compound, or alloy characterized by high electrical conductivity'. ...
en.wikipedia.org/wiki/Metal

Cheers
JOHN

Not according to periodic table! Carbon is in the non-metal group. I always remember how strange it is that sodium--- found in table salt is considered a metal.

Foggy

[fstbttms]

Originally Posted by dubhouse

I'd like advice on my situation. I had a new prop installed in March. I recently cleaned the hull and checked the prop and the prop zinc is gone. There are two prop shaft zincs, one of which is half gone. Is this a normal amount of time to have to replace the zincs ?

There are also tiny white spots on the prop which look like tiny little donuts and are rough to the touch. Is this corrosion or some sort of marine growth ?

I'm late to this thread but here is my $.02 none-the-less. Your zincs are well depleted or completely gone in 6 months. This is on the short end of the normal depletion rate, but is not unusual. Typically, one would hope to get 6-9 months out of your zincs, more depending on the weight of the zinc. The white spots do not sound like corrosion to me. Sometimes white deposits are indicative of corrosion, but they look more like little white pimples, not doughnuts.

[Beausoleil]

Originally Posted by foggysail

Not according to periodic table! Carbon is in the non-metal group. I always remember how strange it is that sodium--- found in table salt is considered a metal.

Foggy

FWIW, most all salts contain a metal: sodium chloride, epsom salt (magnesium sulfate), calcium chloride, potassium nitrate, etc.

Liquid sodium was used in early nuclear sub reactors as a cooling agent because of its excellent thermal conductivity. It turns out that liquid sodium is a better conductor of heat than mercury (also a decent electrical conductor), and replaced the mercury that was used in early reactors... I'm not sure what the most recent subs use - too lazy to google it

[foggysail]

Originally Posted by Beausoleil

FWIW, most all salts contain a metal: sodium chloride, epsom salt (magnesium sulfate), calcium chloride, potassium nitrate, etc.

Liquid sodium was used in early nuclear sub reactors as a cooling agent because of its excellent thermal conductivity. It turns out that liquid sodium is a better conductor of heat than mercury (also a decent electrical conductor), and replaced the mercury that was used in early reactors... I'm not sure what the most recent subs use - too lazy to google it

I worked nights at Electric Boat one year while matriculated at URI. I remember sodium being used but I recall they had some corrosion problems with pipes. That was one interesting place to work. Some of their pipes were almost pure nickel. I remember seeing one pipe about 2" in outside diameter with an inside diameter of about 1/2 inch! But that was years ago and my chemistry knowledge has left me along with my brown hair. Electrical engineering, that is another matter.

Foggy

[perchance]

It is nice to know that so many are well versed in chemistry and physics but I don't that answers the OPs question IMHO.

[bruce smith]

Could the "little white donuts" be barnykills that got "electrocuted "?
I have noticed that when props go "funny" ,it can be felt on the blade edges first. Where are these donuts on the wheel?

[gettinthere]

post a picture of this issue