Cavitation?

[Hooky.]

Maybe not a dumb question and I'm sure I'm not the only one that doesn't fully understand the science behind it but I'm just wanting to know what exactly is meant by cavitation when it is mentioned in relation to propellor erosion. :confusuion:

What actually causes the prop corrosion/erosion and what is the exact definition of cavitation?

cheers :grogon:

hooky

[Hooky.]

Well there you go.

Thanks for that fella's.

So from that I would assume that it is basically caused by the motor been too high or even out of the water when underway.

EDIT: or maybe not.

Thanks again and Pedro, I'll have a read of that link tonight when I "have more time". thanks. :thumbsup:

cheers :grogon:

hooky

Edited September 27, 2004 by hooky

[Grantm]

Hey Fishn,

I like your cav theorys

Just a quick comment on corrosion/errosion with cavitation. It is my belief that it is more errosion than corrosion with a cavitating prop. A prop spinning in aerated water is like it is spinning in sand and eats away the alloy. Aerated water is very abrasive.

This is totaly seperate to corrosion from electrolisis for which we use a zinc anode.

Cheers

[Grantm]

Fishn Mate your dead right. They dont last long on a tinnie with especially with a bit of electrical gear in it.

The motor AND the boat need them I reckon. If there are any dodgy electrical connections they will eat away in no time as well.

Another overlooked thing with anodes is the need to clean off any paint before fitting it otherwise its useless.

:gleam:

[Grantm]

Spot on Fishn,

All types of metal and alloy will always try to return to their natural state by way of electrolysis. All metals are rated from 'cathodic' to 'anodic' .Cathodic metals like gold, platinum etc take forever to disolve where anodic metal like aluminium, cast iron etc disolve quicker.

By putting something that disolves quicker than alloy on your boat ie zinc, it will attract the electrolysis to it and disolve instead of the alloy.

Therefore by not having a zinc anode anything alloy or aluminim will start to disolve. Electrical devices poorly fitted speed up the process.

Good example is Falcon cylinder heads. They have crap electraicals and therefore the water jackets corrode quickly.

Its a natural phenomenom, the metal we use is just trying to go back to the way it was before we mined it.

GEEZ im a dead set fountain of useless information. :ohyeh:

[Hooky.]

GEEZ im a dead set fountain of useless information. :ohyeh:

'Ya too modest Grant, some very good info has come from your input along with the other contributors to this thread.

I hope it turned out to be helpful for many others as well. :thumbsup:

I sure learnt a lot of things from the replies.....Thanks all.

cheers :grogon:

hooky