I got lucky!

[Donna]

In prep for my Bahamas trip, I called my diver to take my prop off as it was having a vibration issue. It needed refurbishing. What I didn't know at the time was it's a bronze prop. The refurbishing cost is substantial, BUT, my diver said he has only seen 3 in his career and not only is it the best, it will last a lifetime!

There has been so much guessing with this vessel since the day I bought her because it was an estate sale, no manuals, etc. I finally got lucky!

I love her more everyday!

 

[FoxtrotCharlie]

Congrats!! And good luck with the crossing to the Bahamas!!

 

[bayview]

I'm confused. Most props are some form of bronze.

 

[Hotrod]

I'm confused. Most props are some form of bronze.

Well ,that makes two of us. I hope the lady was not played.

 

[sunchaser]

Nibral is the choice for most recreational props on the boats commonly found on TF. Nickel, bronze and aluminum alloy.

Donna, how did the diver know the difference between a Nibral vs a bronze prop?

 

[Donna]

It went to a machine shop. No I wasn't played.

 

[bayview]

I think NIBRAL and such are stronger and thus harder to reform than simple tin bronze so my confusion continues.

 

[boatpoker]

Couldn't resist ... 99% of the propellers on cruising boats are "Manganese bronze" which is actually classed as a brass due to it's high zinc content and subject to dezincification if cathodic protection systems are not kept up or if stray current is an issue. Nibral is a proprietary bronze alloy and quite rare due to their high cost. True bronze props are very rare again due to their very high cost.

 

[dhmeissner]

These are very popular and what is on my boat. The original was what they consider "pink" so I purchased a reconditioned Michigan prop. What I didn't know at the time I installed it was described in a recent post, so I need to check the fit at my next haul out.

https://www.miwheel.com/propellers/brands/michigan-propellers/

 

[boatpoker]

These are very popular and what is on my boat. The original was what they consider "pink"

The "pink" colour indicates de-zincification of a manganese bronze (brass) propeller.

 

[Lou_tribal]

Stupid question but I cannot resist... is there any usage of plastic for propeller (except for inflatable fishing boat with outboard)?

 

[dhmeissner]

First Carbon Fiber Main Propeller Installed On a Merchant Ship – gCaptain

 

[Donna]

Couldn't resist ... 99% of the propellers on cruising boats are "Manganese bronze" which is actually classed as a brass due to it's high zinc content and subject to dezincification if cathodic protection systems are not kept up or if stray current is an issue. Nibral is a proprietary bronze alloy and quite rare due to their high cost. True bronze props are very rare again due to their very high cost.

And I thank you. Yes it is true bronze.

Didn't feel like explaining it after the "the lady didn't get played", comment.

Almost all the work on the boat including engine work is done by me and if I don't know, I ask. I can assure anyone that it would take a village to play me. I like my research too much.

 

[BandB]

Wifey B: Are you repeatedly lucky or is it your attitude? You love your boat and you have worked your...ok, careful girl, language......you've worked very hard getting it ready. You've invested so much of you in it. Others might be whining about their horrible luck that they have to spend money with a prop shop. You're happy it's there being repaired and then the news you received you accepted as another positive. Thankfully, boatpoker was able to respond to all the doubters. However, you were going to be happy with whatever it was, because you love your boat, you knew there were some costs ahead and costs owning it, and you're focused on the fun ahead.

Oh, I hope you just have the best time ever in the Bahamas.

 

[BandB]

And I thank you. Yes it is true bronze.

Didn't feel like explaining it after the "the lady didn't get played", comment.

Almost all the work on the boat including engine work is done by me and if I don't know, I ask. I can assure anyone that it would take a village to play me. I like my research too much.

Wifey B: Some ladies aren't easily played. They may be beautiful and perceived automatically by some as not being tough, but you start trying to play them and you'll find out the hard way. I'd never underestimate Donna.

 

[Donna]

Wifey B: Are you repeatedly lucky or is it your attitude? You love your boat and you have worked your...ok, careful girl, language......you've worked very hard getting it ready. You've invested so much of you in it. Others might be whining about their horrible luck that they have to spend money with a prop shop. You're happy it's there being repaired and then the news you received you accepted as another positive. Thankfully, boatpoker was able to respond to all the doubters. However, you were going to be happy with whatever it was, because you love your boat, you knew there were some costs ahead and costs owning it, and you're focused on the fun ahead.

Oh, I hope you just have the best time ever in the Bahamas.

Thanks! I hope you are having a blast!!!!

 

[dhmeissner]

Hey Donna,

This is what I was referring to about fitting the prop back on the shaft...

Lap Fitting A Propeller To A Shaft Photo Gallery by Compass Marine How To at pbase.com

 

[BandB]

Thanks! I hope you are having a blast!!!!

Wifey B: Always. Just got home from a trip to Miami. Short trip but two days there with our best and closest girlfriend and just the three of us enjoying a trip together. Were going to Key West initially but decided to stop short due to sea conditions.

 

[Art]

I'm certain your boat prop looks good in bronze, Donna! And, all tuned up, that prop should give you ears of great cruzen!

 

[AKDoug]

I thought bronze was normal and common in low horsepower applications and Nibral in higher horsepower. Not being picky here, I do love to be informed. My vessel only has 50 hp and has a 3 bladed bronze prop, my friend's NT 32 has 220 hp and his is five blades and Nibral. I thought the bronze props were lower cost as well... When I priced a new prop for my boat (just for fun) it was only offered in bronze.

 

[boatpoker]

I thought bronze was normal and common in low horsepower applications and Nibral in higher horsepower. Not being picky here, I do love to be informed. My vessel only has 50 hp and has a 3 bladed bronze prop, my friend's NT 32 has 220 hp and his is five blades and Nibral. I thought the bronze props were lower cost as well... When I priced a new prop for my boat (just for fun) it was only offered in bronze.

Everyone uses the term bronze when they actually mean manganese bronze. You have to be ultra specific about this even when talking to a pro prop guy. You must clearly ask them for the type of bronze.

Suggest you google the terms.

 

[BandB]

I thought bronze was normal and common in low horsepower applications and Nibral in higher horsepower. Not being picky here, I do love to be informed. My vessel only has 50 hp and has a 3 bladed bronze prop, my friend's NT 32 has 220 hp and his is five blades and Nibral. I thought the bronze props were lower cost as well... When I priced a new prop for my boat (just for fun) it was only offered in bronze.

Most that are called bronze are an alloy. Read boatpoker's post. Only a very few are pure bronze.

 

[AKDoug]

I have been trying to research that online but the info is spotty and less than educationally complete. I would think that unalloyed bronze would be really soft. Finding lots of reference to aluminum alloyed bronze as well as manganese bronze, no reference to unalloyed bronze propellers...

 

[Peter B]

Most that are called bronze are an alloy. Read boatpoker's post. Only a very few are pure bronze.

Ah, I think you'd find that bronze is an alloy anyway. Just the composition of the various elements can be varied to make different type of bronze.

https://www.quora.com/What-is-bronze-and-how-is-it-made

 

[BandB]

Ah, I think you'd find that bronze is an alloy anyway. Just the composition of the various elements can be varied to make different type of bronze.

https://www.quora.com/What-is-bronze-and-how-is-it-made

You are correct. Let me rephrase,. It's the bronze alloy and not the other combination tossed in. It's as boatpoker described. Basically a higher grade of bronze for lack of scientific knowledge. Unusual quality.

 

[AKDoug]

Copper and tin from what I am reading, the copper and zinc is where de-zincification and "pinking" become an issue. The latest greatest is copper and aluminum, which is thinner and stiffer as well as being stronger...

 

[C lectric]

There are many different bronzes. All bronzes are alloys of some nature. Copper is the main element with zinc, tin, aluminum, lead, nickel and so on being used in varying % to modify the basic copper for cost, strength, corrosion resistance, ease of working . A true bronze has no zinc in it although there are some where the zinc is such a small % that it is still suitable for seawater use. Most use tin with nickel or aluminum and other metals for modification for specific uses.

Most low power propellers are what is called Manganese bronze which is NOT a true bronze as there is too much zinc in it, ~40%. It is prone to failure as seawater will eat the zinc out of it unless it is protected with a zinc, or other, anode. Although cheaper than other alloys they are NOT cheap. They also are weaker than many other alloys although more than strong enough for lower power applications like many of our boats. They are also easier to repair than most of the other stronger alloys. Just be sure they are protected.

Manganese Bronze gives thousands of boats good service over many years as long as they are protected properly.

Some of the other alloys are used for much higher corrosion resistance and , much higher strength thus often thinner blades but at the cost of $$$ and tougher repairs. High powered boats that are intended to plane will usually use one of these more expensive, stronger alloys.

Yes, pinking is a sign of dezincification and a sign that the anode is missing, inadequate, or not connected even if present. This will be an expensive problem if not caught and dealt with early.

 

[boatpoker]

There are many different bronzes. All bronzes are alloys of some nature. Copper is the main element with zinc, tin, aluminum, lead, nickel and so on being used in varying % to modify the basic copper for cost, strength, corrosion resistance, ease of working . A true bronze has no zinc in it although there are some where the zinc is such a small % that it is still suitable for seawater use. Most use tin with nickel or aluminum and other metals for modification for specific uses.

Most low power propellers are what is called Manganese bronze which is NOT a true bronze as there is too much zinc in it, ~40%. It is prone to failure as seawater will eat the zinc out of it unless it is protected with a zinc, or other, anode. Although cheaper than other alloys they are NOT cheap. They also are weaker than many other alloys although more than strong enough for lower power applications like many of our boats. They are also easier to repair than most of the other stronger alloys. Just be sure they are protected.

Manganese Bronze gives thousands of boats good service over many years as long as they are protected properly.

Some of the other alloys are used for much higher corrosion resistance and , much higher strength thus often thinner blades but at the cost of $$$ and tougher repairs. High powered boats that are intended to plane will usually use one of these more expensive, stronger alloys.

Yes, pinking is a sign of dezincification and a sign that the anode is missing, inadequate, or not connected even if present. This will be an expensive problem if not caught and dealt with early.

Let me try and simplify what C Lectric is saying ...

"Brass" refers not to a specific metallurgy but to a class of metal alloys somewhat defined by zinc content. Included in this group for example is "admiralty brass", "naval brass", "manganese bronze" etc. So to say something is "brass" really does not tell you much.

"Bronze" also refers to a class of metals including "phosphor bronze", "silicon bronze" etc. So once again calling something just "bronze" does not really tell you much.

 

[Donsan]

This thread has turned out to be quite educational for me. Our old Fu Hwa had a bronze propeller and I have no idea what the alloy was. On the Great Lakes, it doesn't sound like it matters.

Could some one clue me in on why outboard and stern drives use aluminum and stainless steel vice bronze? I suspect it is due to the amount of time the propeller spends in the water. Can other metals be used for trawler propellers?

Quite frankly, I have always taken propellers for granted.

 

[sunchaser]

I have been trying to research that online but the info is spotty and less than educationally complete. I would think that unalloyed bronze would be really soft. Finding lots of reference to aluminum alloyed bronze as well as manganese bronze, no reference to unalloyed bronze propellers...

Which is why NIBRAL is so popular, especially on highly loaded props. No zinc and stronger than pure bronze. There are many good sources and information on the Internet as BP suggests. Michigan Wheel as previously mentioned is one.