Can I Zinc INSIDE the hull?

[noelex 77]

Originally Posted by MarkJ

The 2 thru hulls i worry about are only a foot, and 2 feet from the keel.

This is no problem providing the thru hulls are not in electrical contact with the keel. Galvanic corrosion needs both metals immersed in an electrolite (seawater) AND electrical contact.

[estarzinger]

Originally Posted by MarkJ

At the end of this year I am doing 6 months in a locked boat basin

St Kathrine's docks?

[Sandero]

So can any answer the question...

What are the visible to the naked eye signs that your bronze thru hulls are "deteriorating"?

[estarzinger]

They develop a pink color to them, rather than normal bronze color. and there is usually some visible surface pitting.

[MarkJ]

Originally Posted by estarzinger

St Kathrine's docks?

No. Those bums won't give me a break on the rates.
Limehouse will and is just down the road

[MarkJ]

See the pink on the valve. It's not disco pink...

The buffed area on the valve outer wall had water leaking through it by some imperfection.

On the top surface there's pink but where it's been wire brushed away shows the metal inside is fine.

It's been installed for 2 years.

[a64pilot]

[QUOTE=Guy;2386404]

Originally Posted by a64pilot

RPM is speed. I doubt you will find a reference to a constant RPM prop, just constant speed.



There is no real difference between a variable pitch prop and what you are calling a constant speed prop. The constant speed prop has a governor, which is controlled by the RPM of the flyweights. Both props are variable pitch, one is controlled automaticly and one, some other way.

This isn't the place, but hope thread drift isn't too much
A variable pitch prop you set the pitch, it won't change unless you change it, point the nose uphill and the engine RPM will decrease, point it downhill, it increases, pitch remains constant, RPM varies.
A constant speed prop is just that, point the nose uphill and pitch is reduced to maintain RPM, opposite in descent of course, pitch varies to maintain RPM.
In one you set RPM and pitch varies, the other you set pitch, and RPM varies.
Variable pitch props were before my time as I'm only approaching 60, I only have experience with constant speed. I have never even seen a variable pitch prop.
This is not to be confused with ground adjustable props of course.

There are boating correlations of course, an Autoprop is more of a constant speed as if you increase boat speed like motorsailing, the prop increases pitch automatically to keep the engine loaded.
A Hunstead I think is a variable pitch, you control pitch, if you increase speed like motorsailing, you have to increase pitch to keep the same load on the engine.

[MarkJ]

Originally Posted by a64pilot

This isn't the place, but hope thread drift isn't too much
A variable pitch prop you set the pitch,.

Thread drift? Aircraft propellers when the thread is about chucking a zinc in the toilet water???


In 25 days you will be too busy to write this tripe 😂😂😂😂

[SV Bacchus]

Originally Posted by MarkJ

As for the disgusting crude remarks about a certain young lady... leaving the restaurant quickly (I don't like paying) she fell flat on her face. But immediately bounced straight back up!

😊

If she bounced up that quickly I don't think her face ever hit.

[Cadence]

Originally Posted by MarkJ

Thread drift? Aircraft propellers when the thread is about chucking a zinc in the toilet water???


In 25 days you will be too busy to write this tripe 😂😂😂😂

Mark,

Years ago I met a guy won't say friend, that had a prop. which the pitch was variable from inside the boat. As I recall he had to have it shipped from and custom made in Denmark. It had a sleeve around the shaft that could be moved fore and aft to adjust the pitch. He had built the 65" ferro sailboat.

Re: the zinc in the head. It helps not getting electrolysis of the balls.

[Bleemus]

Hundestat variable pitch propeller. Now the thread drift is complete.

[TrentePieds]

Well, not quite complete :-) The correct spelling is "Hundested", and the variable - more correctly: controlable pitch - propeller was standard issue on fishing vessels when I wuz a lad. They were married without benefit of reduction gear (although some had a driving dog that could be thrown out of engagement) to one-lung semi-diesels. Sternway was achieved by simply "laying the pitch over" by turning a handwheel with a crank handle that had something like something like six turns stop to stop.

The installation was totally elegant and made maneuvering in narrow quarter an absolute piece of cake.

Here is a short video of how it was done:

[TrentePieds]

Whoa! Misclicked myself :-) Clip will follow!

TP

[Cadence]

Originally Posted by Bleemus

Hundestat variable pitch propeller. Now the thread drift is complete.

Even if drift, at least someone knew about the prop from Denmark There has been some kidding about bronze seacock/through hull deterioration. It is a serious topic.
They do get crystalline and can get brittle over time and snap. I'm guessing wiring them to the engine and letting the shaft zinc take the beating is the best way? Better than my suggestion of a zinc in the head or Mark's of bilge water.
I suppose a zinc could be mounted thru hull and wired to the trough hull. Make it big an wire the rigging to it as a ground.

[Bleemus]

Sorry for the mispelling. We had one on the Baltic 76 I worked on. Hooked up to an 8cyl Mercedes you could dial the grunt into it and power the boat around 10 knots at 1300 rpm if I remember correctly. Brilliant piece of gear.